Journal articles: 'C2 fragment'

1

Mackay, Donald G., Christopher B. Hadley, and Joel H. Schwartz. "Relations between emotion, illusory word perception, and orthographic repetition blindness: Tests of binding theory." Quarterly Journal of Experimental Psychology Section A 58, no. 8 (November 2005): 1514–33. http://dx.doi.org/10.1080/02724980443000728.

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This study reports effects of meaning and emotion (taboo vs. neutral words) on an illusory word (IW) phenomenon linked to orthographic repetition blindness (RB). Participants immediately recalled rapid serial visual presentation (RSVP) lists consisting of two critical words (C1 and C2) containing shared letters, followed by a word fragment: for example, lake (C1) brake (C2) ush (fragment). For neutral critical words, participants often recalled C1, but not C2 or the fragment, reporting instead a nonoccurring or illusory word: here, brush (a blend of C2 and the fragment). Forward RB (defined as reduced report of orthographically similar C2s) was more common for neutral than for taboo C2s, and taboo IWs were reported significantly more often than were neutral IWs. Moreover, when both C2 and the potential IW were taboo, a new phenomenon emerged: Participants reliably reported both the IW and the intact C2. These and other results supported a binding theory of the IW phenomenon and orthographic RB.

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2

Kjalke, M., K. G. Welinder, and C. Koch. "Structural analysis of chicken factor B-like protease and comparison with mammalian complement proteins factor B and C2." Journal of Immunology 151, no. 8 (October 15, 1993): 4147–52. http://dx.doi.org/10.4049/jimmunol.151.8.4147.

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Abstract Chicken complement factor B-like protease is a glycoprotein of 95 kDa. Activation of chicken serum complement with inulin cleaved the B-like protease into an N-terminal Ba fragment of 37 kDa and a C-terminal Bb fragment of 60 kDa. The whole protein and the two fragments were purified by affinity chromatography using mAb to chicken Ba or Bb followed by ion exchange chromatography. Amino acid sequencing showed that chicken B-like protease was cleaved at a site homologous to that cleaved in mammalian complement components B and C2 on activation. Limited tryptic digestion of the B-like protease generated fragments similar to Ba and Bb. More than 200 residues of the Ba sequence and two N-linked glycosylation sites were established by amino acid sequencing of peptides derived by digestion with four proteases. Comparison of human and mouse C2 and B sequences indicated a slower evolutionary rate for B (85% sequence identity) than for C2 (74% sequence identity). Comparison of chicken Ba to human and mouse C2b and Ba showed 42 to 45% sequence identity with respect to C2b fragments, and 46 to 49% sequence identity with respect to Ba fragments. Taking the slower evolutionary rate of factor B into account, chicken factor B-like protease seems to be equally related to mammalian complement components B and C2, and the B-like protease most likely represents the present-day descendant of a common ancestral protein for mammalian B and C2. This conclusion is in agreement with the requirement for the B-like protease in both classical and alternative activation pathways for chicken complement, and with the apparent lack of a chicken serum protein with exclusive C2 activity.

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WAKABAYASHI, T., H. SHIROMARU, S. SUZUKI, K. KIKUCHI, and Y. ACHIBA. "C2-LOSS FRAGMENTATION OF HIGHER FULLERENES AND METALLOFULLERENES." Surface Review and Letters 03, no. 01 (February 1996): 793–98. http://dx.doi.org/10.1142/s0218625x96001431.

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Photofragmentation investigations were performed by using chromatographically isolated pure samples of higher fullerenes and metallofullerenes. Quite similar distributions of fragments were commonly observed for five different fullerenes, and this fact supports the presence of a “scrambled-cage” structure in a highly excited fullerene cage. An enhancement of the C 60 and C 70 signals was also observed as a result of “delayed C 2-loss” fragmentation within a time scale of about 60 µs after photoexcitation. Photodissociation study of mono- and di-metallofullerenes revealed the qualitative difference in the fragment distributions between them, suggesting that LaC 82 would possess an endohedral, and Sc 2 C 84 an exohedral, form.

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4

Okagaki, T., F. E. Weber, D. A. Fischman, K. T. Vaughan, T. Mikawa, and F. C. Reinach. "The major myosin-binding domain of skeletal muscle MyBP-C (C protein) resides in the COOH-terminal, immunoglobulin C2 motif." Journal of Cell Biology 123, no. 3 (November 1, 1993): 619–26. http://dx.doi.org/10.1083/jcb.123.3.619.

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A common feature shared by myosin-binding proteins from a wide variety of species is the presence of a variable number of related internal motifs homologous to either the Ig C2 or the fibronectin (Fn) type III repeats. Despite interest in the potential function of these motifs, no group has clearly demonstrated a function for these sequences in muscle, either intra- or extracellularly. We have completed the nucleotide sequence of the fast type isoform of MyBP-C (C protein) from chicken skeletal muscle. The deduced amino acid sequence reveals seven Ig C2 sets and three Fn type III motifs in MyBP-C. alpha-chymotryptic digestion of purified MyBP-C gives rise to four peptides. NH2-terminal sequencing of these peptides allowed us to map the position of each along the primary structure of the protein. The 28-kD peptide contains the NH2-terminal sequence of MyBP-C, including the first C2 repeat. It is followed by two internal peptides, one of 5 kD containing exclusively spacer sequences between the first and second C2 motifs, and a 95-kD fragment containing five C2 domains and three fibronectin type III motifs. The C-terminal sequence of MyBP-C is present in a 14-kD peptide which contains only the last C2 repeat. We examined the binding properties of these fragments to reconstituted (synthetic) myosin filaments. Only the COOH-terminal 14-kD peptide is capable of binding myosin with high affinity. The NH2-terminal 28-kD fragment has no myosin-binding, while the long internal 100-kD peptide shows very weak binding to myosin. We have expressed and purified the 14-kD peptide in Escherichia coli. The recombinant protein exhibits saturable binding to myosin with an affinity comparable to that of the 14-kD fragment obtained by proteolytic digestion (1/2 max binding at approximately 0.5 microM). These results indicate that the binding to myosin filaments is mainly restricted to the last 102 amino acids of MyBP-C. The remainder of the molecule (1,032 amino acids) could interact with titin, MyBP-H (H protein) or thin filament components. A comparison of the highly conserved Ig C2 domains present at the COOH-terminus of five MyBPs thus far sequenced (human slow and fast MyBP-C, human and chicken MyBP-H, and chicken MyBP-C) was used to identify residues unique to these myosin-binding Ig C2 repeats.

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Wada, Yoriko, Hiroshi Akagi, Takayuki Kumada, Ryuji Itakura, and Tomonari Wakabayashi. "Mass-Resolved Momentum Imaging of Three Dichloroethylene Isomers by Femtosecond Laser-Induced Coulomb Explosion." Photochem 2, no. 3 (September 16, 2022): 798–809. http://dx.doi.org/10.3390/photochem2030051.

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Coulomb explosion experiments using linearly polarized intense 60 fs laser pulses were conducted for structural characterization of three dichloroethylene (DCE) isomers, 1,1-DCE, cis-1,2-DCE, and trans-1,2-DCE. Under relatively low laser intensity at 1.8 × 1014 W/cm2, mass-resolved momentum imaging (MRMI) for selected fragment ions of 35Cl+ and C2+ revealed different patterns for the three isomers. The C2+ ion fragmented from multiply charged trans-1,2-DCE was forced to leave perpendicularly to the direction of the laser polarization, due to recoil forces from adjacent cations. In contrast, the fast ions of C2+ from cis-1,2-DCE exhibited an isotropic distribution, whereas the fast ions of C2+ from 1,1-DCE recoiled along the laser polarization together with the slow C2+ ions, and thereby distinction of the three isomers was demonstrated. Coulomb explosion occurs predominantly at specific orientation, which is useful for potential applications of MRMI analysis to molecular structure assays.

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6

Lie, W. R., M. F. Rothschild, and C. M. Warner. "Mapping of C2, Bf, and C4 genes to the swine major histocompatibility complex (swine leukocyte antigen)." Journal of Immunology 139, no. 10 (November 15, 1987): 3388–95. http://dx.doi.org/10.4049/jimmunol.139.10.3388.

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Abstract Three miniature swine lines, inbred for swine leukocyte antigen (SLA) haplotypes, a, c, and d, and a recombinant line, haplotype g, were analyzed for possible restriction fragment length polymorphisms (RFLP) by Southern blot hybridization with human C2, factor B (Bf), and C4 specific probes. The search for RFLP by using a human C2 probe failed to reveal any variants. However, a Taq I polymorphism was identified with the human Bf probe and Bam HI and Pvu II polymorphisms were identified with the human C4 probe. Overlapping restriction fragments were found with the C2 and Bf probes, which strongly suggests close linkage of C2 and Bf genes in swine. Segregation analyses of the Bf and C4 polymorphisms indicated that the polymorphic fragments followed a Mendelian pattern of inheritance. The recombinant haplotype g, which expresses class I genes of haplotype c and class II genes of haplotype d, was shown to produce an identical RFLP pattern, by using the Bf and C4 probes, as haplotype d, but different from that of haplotype c. This indicates that there is a close association of [C4-Bf-C2] and class II genes in miniature swine. Although these data do not show conclusively the location of the [C4-Bf-C2] genes, it is hypothesized that swine [C4-Bf-C2] genes are located between the class II and class I genes, as has been demonstrated in mouse and man.

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7

ur Rashid, Haroon, Frankie Leung, William Lu, Boris Fung, and S. P. Chow. "BIOMECHANICAL EVALUATION OF PLATE OSTEOSYNTHESIS FOR AO TYPE C2 FRACTURE OF THE DISTAL RADIUS — A CADAVER STUDY." Hand Surgery 08, no. 02 (December 2003): 151–56. http://dx.doi.org/10.1142/s0218810403001650.

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An AO type C2 distal radius fracture was simulated in a cadaver model by creating a metaphyseal defect of 5 mm and an intra-articular defect of 2 mm. Five different methods of plate osteosynthesis were tested biomechanically in each of six fresh cadaveric hands. Biomechanical testing suggested that cement augmented plating plus screws in the distal fragment was the strongest. Dorsal and volar plating plus screws on both sides of the distal fragment had the same effect of restoring stiffness and load transmission pattern as fixation with double plating plus volar screws alone. Fixation with plating plus dorsal screws was significantly weaker than these three methods, and double buttress plating with no screws in the distal fragments was the weakest.

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8

Ali, Yasir, Hina Imtiaz, Muhammad Mutaal Tahir, Fouzia Gul, Umair Ali Khan Saddozai, Ashfaq ur Rehman, Zhi-Guang Ren, Saadullah Khattak, and Xin-Ying Ji. "Fragment-Based Approaches Identified Tecovirimat-Competitive Novel Drug Candidate for Targeting the F13 Protein of the Monkeypox Virus." Viruses 15, no. 2 (February 19, 2023): 570. http://dx.doi.org/10.3390/v15020570.

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Monkeypox is a serious public health issue in tropical and subtropical areas. Antivirals that target monkeypox proteins might lead to more effective and efficient therapy. The F13 protein is essential for the growth and maturation of the monkeypox virus. F13 inhibition might be a viable therapeutic target for monkeypox. The in silico fragment-based drug discovery method for developing antivirals may provide novel therapeutic options. In this study, we generated 800 compounds based on tecovirimat, an FDA-approved drug that is efficacious at nanomolar quantities against monkeypox. These compounds were evaluated to identify the most promising fragments based on binding affinity and pharmacological characteristics. The top hits from the chemical screening were docked into the active site of the F13 protein. Molecular dynamics simulations were performed on the top two probable new candidates from molecular docking. The ligand–enzyme interaction analysis revealed that the C2 ligand had lower binding free energy than the standard ligand tecovirimat. Water bridges, among other interactions, were shown to stabilize the C2 molecule. Conformational transitions and secondary structure changes in F13 protein upon C2 binding show more native three-dimensional folding of the protein. Prediction of pharmacological properties revealed that compound C2 may be promising as a drug candidate for monkeypox fever. However, additional in vitro and in vivo testing is required for validation.

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9

ZHOU, Zuozhong, Dong SUO, Zhenyu YANG, Lin CHEN, Taishan HU, and Zhujun YAO. "Stereoselective Synthesis of the Functionalized C2-C10 Fragment of Clavulactone." Chinese Journal of Chemistry 27, no. 1 (January 2009): 135–40. http://dx.doi.org/10.1002/cjoc.200990006.

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10

Oglesby, T. J., M. A. Accavitti, and J. E. Volanakis. "Evidence for a C4b binding site on the C2b domain of C2." Journal of Immunology 141, no. 3 (August 1, 1988): 926–31. http://dx.doi.org/10.4049/jimmunol.141.3.926.

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Abstract We raised murine mAb against human C protein C2. The representative mAb 3A3.3 (IgG1 kappa) recognized an epitope on the C2b domain of C2, as determined by binding and inhibition of binding radioassays. The hemolytic activity of purified human C2 and of C2 in normal human serum was inhibited by the mAb. The rate of decay of the C3-convertase at 30 degrees C was not affected by the mAb. C2 binding to EAC4b was inhibited by intact IgG and the Fab fragment of the mAb; 50% inhibition required 1 microgram/ml of either. The data suggest the presence of a C4b-binding site on the C2b domain of C2 and that the mAb recognizes an epitope at, or adjacent to, this site. The C2b portion of the C2 molecule may be important in assembly of the classical pathway C3-convertase.

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11

Simon, S., Z. Awdeh, R. D. Campbell, P. Ronco, S. J. Brink, G. S. Eisenbarth, E. J. Yunis, and C. A. Alper. "A restriction fragment of the C2 gene is a unique marker for C2 deficiency and the uncommon C2 allele C2*B (a marker for type 1 diabetes)." Journal of Clinical Investigation 88, no. 6 (December 1, 1991): 2142–45. http://dx.doi.org/10.1172/jci115545.

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12

Fijnvandraat, Karin, Patrick H. N. Celie, Ellen A. M. Turenhout, Jan W. ten Cate, Jan A. van Mourik, Koen Mertens, Marjolein Peters, and Jan Voorberg. "A Human Alloantibody Interferes With Binding of Factor IXa to the Factor VIII Light Chain." Blood 91, no. 7 (April 1, 1998): 2347–52. http://dx.doi.org/10.1182/blood.v91.7.2347.

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Abstract Inhibitory antibodies directed against factor VIII develop in a substantial number of patients with hemophilia A as a consequence of factor VIII replacement therapy. These antibodies usually recognize discrete epitopes within the A2 and/or the C2 domains of factor VIII. Here, we have characterized the antibodies present in the plasma of a patient affected by severe hemophilia A. The antibodies reacted readily with the metabolically labeled factor VIII light chain and fragments thereof when analyzed by immunoprecipitation. The inhibitory activity could be neutralized by the complete light chain, whereas only slight neutralization occurred with a fragment comprising the isolated C2 domain. Binding of the majority of antibodies to in vitro synthesized factor VIII fragments was dependent on the presence of amino acid residues Gln1778-Met1823, a region known to contain a factor IXa binding site. Functional characterization showed that purified IgG from the patient's serum inhibited binding of factor IXa to immobilized factor VIII light chain in a dose-dependent manner. These data indicate that human alloantibodies may inhibit factor VIII activity by interfering with factor IXa–factor VIIIa complex assembly.

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13

Fijnvandraat, Karin, Patrick H. N. Celie, Ellen A. M. Turenhout, Jan W. ten Cate, Jan A. van Mourik, Koen Mertens, Marjolein Peters, and Jan Voorberg. "A Human Alloantibody Interferes With Binding of Factor IXa to the Factor VIII Light Chain." Blood 91, no. 7 (April 1, 1998): 2347–52. http://dx.doi.org/10.1182/blood.v91.7.2347.2347_2347_2352.

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Inhibitory antibodies directed against factor VIII develop in a substantial number of patients with hemophilia A as a consequence of factor VIII replacement therapy. These antibodies usually recognize discrete epitopes within the A2 and/or the C2 domains of factor VIII. Here, we have characterized the antibodies present in the plasma of a patient affected by severe hemophilia A. The antibodies reacted readily with the metabolically labeled factor VIII light chain and fragments thereof when analyzed by immunoprecipitation. The inhibitory activity could be neutralized by the complete light chain, whereas only slight neutralization occurred with a fragment comprising the isolated C2 domain. Binding of the majority of antibodies to in vitro synthesized factor VIII fragments was dependent on the presence of amino acid residues Gln1778-Met1823, a region known to contain a factor IXa binding site. Functional characterization showed that purified IgG from the patient's serum inhibited binding of factor IXa to immobilized factor VIII light chain in a dose-dependent manner. These data indicate that human alloantibodies may inhibit factor VIII activity by interfering with factor IXa–factor VIIIa complex assembly.

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14

Stanton, Bobby J., E. T. Monroe, and E. L. Wehry. "Pump-Probe Laser Photolytic Fragmentation Fluorescence Spectrometry of Isomeric Alkenes." Applied Spectroscopy 48, no. 5 (May 1994): 616–19. http://dx.doi.org/10.1366/0003702944924754.

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The two-laser “pump-probe” photolytic fragmentation fluorescence spectrometry of three octenes and two nonenes is described. Probe-laser-induced C2 fluorescence (Deslandres-d'Azambuja system, C1II g→ A1II u) is detected. The relative C2 fluorescence intensity and spectral patterns exhibited by each alkene are strongly dependent on the probe-laser wavelength. The dependence of the fragment fluorescence intensity on the probe-laser fluence implies that the “probe” laser induces photofragmentation of intermediate species produced by the “photolysis” laser.

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15

Gabbay, D. M., and V. B. Shehtman. "Undecidability of modal and intermediate first-order logics with two individual variables." Journal of Symbolic Logic 58, no. 3 (September 1993): 800–823. http://dx.doi.org/10.2307/2275098.

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The interest in fragments of predicate logics is motivated by the well-known fact that full classical predicate calculus is undecidable (cf. Church [1936]). So it is desirable to find decidable fragments which are in some sense “maximal”, i.e., which become undecidable if they are “slightly” extended. Or, alternatively, we can look for “minimal” undecidable fragments and try to identify the vague boundary between decidability and undecidability. A great deal of work in this area concerning mainly classical logic has been done since the thirties. We will not give a complete review of decidability and undecidability results in classical logic, referring the reader to existing monographs (cf. Suranyi [1959], Lewis [1979], and Dreben, Goldfarb [1979]). A short summary can also be found in the well-known book Church [1956]. Let us recall only several facts. Herein we will consider only logics without functional symbols, constants, and equality.(C1) The fragment of the classical logic with only monadic predicate letters is decidable (cf. Behmann [1922]).(C2) The fragment of the classical logic with a single binary predicate letter is undecidable. (This is a consequence of Gödel [1933].)(C3) The fragment of the classical logic with a single individual variable is decidable; in fact it is equivalent to Lewis S5 (cf. Wajsberg [1933]).(C4) The fragment of the classical logic with two individual variables is decidable (Segerberg [1973] contains a proof using modal logic; Scott [1962] and Mortimer [1975] give traditional proofs.)(C5) The fragment of the classical logic with three individual variables and binary predicate letters is undecidable (cf. Surańyi [1943]). In fact this paper considers formulas of the following typeφ,ψ being quantifier-free and the set of binary predicate letters which can appear in φ or ψ being fixed and finite.

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16

Yu, Y. T., and B. Nadal-Ginard. "Interaction of nuclear proteins with a positive cis-acting element of rat embryonic myosin heavy-chain promoter: identification of a new transcriptional factor." Molecular and Cellular Biology 9, no. 5 (May 1989): 1839–49. http://dx.doi.org/10.1128/mcb.9.5.1839-1849.1989.

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A DNA fragment of the rat embryonic myosin heavy-chain promoter (MHCemb) has been found to specifically bind a nuclear factor (NFe) present in extracts prepared from mouse C2 myoblasts, myotubes, and HeLa cells. The nucleotide sequence of the binding site (BSe) has been identified as 5'-GTGTCAGTCA-3' and was located between -93 and -84. Transient expression studies on MHCemb promoter deletion constructs in C2 myoblasts and C2 myotubes suggested that NFe is a transcriptional factor. Deletion of the NFe-binding site resulted in four- to sixfold and twofold reduction of promoter activity in C2 myotubes and C2 myoblasts, respectively. Furthermore, point mutations at the BSe not only abolished the NFe-binding activity of the MHCemb promoter but also resulted in reduction of the promoter activity to levels similar to those of the deletion constructs in C2 myotubes, myoblasts, and Hela cells (four- to sixfold). Although BSe and the binding site of the recently identified transcriptional factors AP-1 and ATF share significant homology, the results from competition binding assays indicated that NFe is different from both AP-1 and ATF.

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17

Yu, Y. T., and B. Nadal-Ginard. "Interaction of nuclear proteins with a positive cis-acting element of rat embryonic myosin heavy-chain promoter: identification of a new transcriptional factor." Molecular and Cellular Biology 9, no. 5 (May 1989): 1839–49. http://dx.doi.org/10.1128/mcb.9.5.1839.

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A DNA fragment of the rat embryonic myosin heavy-chain promoter (MHCemb) has been found to specifically bind a nuclear factor (NFe) present in extracts prepared from mouse C2 myoblasts, myotubes, and HeLa cells. The nucleotide sequence of the binding site (BSe) has been identified as 5'-GTGTCAGTCA-3' and was located between -93 and -84. Transient expression studies on MHCemb promoter deletion constructs in C2 myoblasts and C2 myotubes suggested that NFe is a transcriptional factor. Deletion of the NFe-binding site resulted in four- to sixfold and twofold reduction of promoter activity in C2 myotubes and C2 myoblasts, respectively. Furthermore, point mutations at the BSe not only abolished the NFe-binding activity of the MHCemb promoter but also resulted in reduction of the promoter activity to levels similar to those of the deletion constructs in C2 myotubes, myoblasts, and Hela cells (four- to sixfold). Although BSe and the binding site of the recently identified transcriptional factors AP-1 and ATF share significant homology, the results from competition binding assays indicated that NFe is different from both AP-1 and ATF.

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18

Caetano, Afonso Cevadinha, Pedro Xavier Fernandes, Raquel Teixeira, Andreia Mercier Nunes, José Miguel Sousa, Clara Azevedo, and José Guimaraes Consciencia. "C2 dens fracture with closed cervical migration of a 6cm humeral fragment." International Journal of Orthopaedics Sciences 4, no. 1h (January 1, 2018): 517–21. http://dx.doi.org/10.22271/ortho.2018.v4.i1h.74.

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19

Hui, Kwok-Min, George L. Orriss, Tilman Schirmer, Bergljót Magnadóttir, Jürg A. Schifferli, and Jameel M. Inal. "Expression of functional recombinant von Willebrand factor-A domain from human complement C2: a potential binding site for C4 and CRIT." Biochemical Journal 389, no. 3 (July 26, 2005): 863–68. http://dx.doi.org/10.1042/bj20050183.

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CRIT (complement C2 receptor inhibitor trispanning) is a newly described transmembrane molecule that is capable of binding C2 via its first extracellular domain (ed1). CRIT competes with C4b for the binding of C2. Previous experiments have suggested that a major binding site for C2 is located on short, almost identical peptide sequences of CRIT-ed1 and the β-chain of C4. The C2 domains involved in binding, however, remain unknown. We cloned the vWFA (von Willebrand factor-A) domain of C2, as it is a region likely to be involved in interactions with other proteins, and were able to functionally express the 25 kDa human complement C2 vWFA domain (amino acids 224–437). The recombinant vWFA protein fixed on MagneHis Ni-Particles bound C4 in normal human serum. The C4 α, β and γ chains were separated by SDS/PAGE and purified separately by electro-elution. The purified C4 chains were then used in a sandwich ELISA, which showed the vWFA to bind C4 only via the C4β chain. In a haemolytic assay, the recombinant vWFA protein inhibited complement activation by the classical pathway in a dose-dependent manner by competing with native C2 for binding to C4b. vWFA bound the ed1 peptide of CRIT as well, and specifically to the 11-amino-acid peptide fragment of ed1 that is known to interact with whole C2. These findings show that the vWFA domain is centrally involved in the C2–CRIT and C2–C4b bindings. The cloned vWFA domain will allow us to dissect out the fine interactions between C2 and CRIT or C4b.

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Zhu, Z. B., S. L. Hsieh, D. R. Bentley, R. D. Campbell, and J. E. Volanakis. "A variable number of tandem repeats locus within the human complement C2 gene is associated with a retroposon derived from a human endogenous retrovirus." Journal of Experimental Medicine 175, no. 6 (June 1, 1992): 1783–87. http://dx.doi.org/10.1084/jem.175.6.1783.

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We have previously described multiallelic restriction fragment length polymorphisms of the C2 gene, suggesting the presence of a variable number of tandem repeats (VNTR) locus. We report here the cloning and sequencing of the polymorphic fragments from the two most common alleles of the gene, a and b. The results confirm the presence of a VNTR locus consisting of a nucleotide sequence, 41 bp in average length, repeated tandemly 23 and 17 times in alleles a and b, respectively. The difference in the number of repeats between the two alleles is due to the deletion/insertion of two noncontiguous segments, 143 and 118 bp long, of allele a, and of a 40-bp segment of allele b. The VNTR region is associated with a SINE (short interspersed sequence)-type retroposon, SINE-R.C2, located within the third intron of the C2 gene. SINE-R.C2 is a member of a previously described large retroposon family of the human genome, apparently derived from the human endogenous retrovirus, (HERV) K10, which is homologous to the mouse mammary tumor virus.

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Xu, Y., and J. E. Volanakis. "Contribution of the complement control protein modules of C2 in C4b binding assessed by analysis of C2/factor B chimeras." Journal of Immunology 158, no. 12 (June 15, 1997): 5958–65. http://dx.doi.org/10.4049/jimmunol.158.12.5958.

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Abstract To identify the complement control protein (CCP) module(s) of C2 that are required for C4b recognition, we constructed a panel of C2/factor B chimeras by substituting intact or partial factor B CCP modules for the corresponding ones of C2. Epitope mapping indicated that the anti-C2b mAb 3A3.3, which inhibits binding of C2 to C4b, reacts with the second CCP of C2 and similarly the anti-Ba mAb HA4-1A, which inhibits binding of factor B to C3b, reacts with the second CCP of factor B. The hemolytic activity of the chimeras CP1, CP2, and CP3a containing CCP1, CCP2, and a fragment of CCP3 of factor B, respectively, was substantially decreased compared with that of wild-type C2. The CP3 and CP1-3 chimeras, in which CCP3 and all three CCP modules of factor B, respectively, were substituted, had no hemolytic activity. Loss of activity could be attributed to the resistance of these two chimeras to C1s cleavage, which was probably due to conformational changes of the cleavage site. The combined results indicate that all three CCP modules of C2 contribute structural elements to the C4b-binding site of C2b. This site has been shown previously to be necessary for the initial binding of C2 to C4b which leads to the formation of the classical pathway C3 convertase.

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22

McMahon, Hilary E. M. "Prion processing: a double-edged sword?" Biochemical Society Transactions 40, no. 4 (July 20, 2012): 735–38. http://dx.doi.org/10.1042/bst20120031.

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The events leading to the degradation of the endogenous PrPC (normal cellular prion protein) have been the subject of numerous studies. Two cleavage processes, α-cleavage and β-cleavage, are responsible for the main C- and N-terminal fragments produced from PrPC. Both cleavage processes occur within the N-terminus of PrPC, a region that is significant in terms of function. α-Cleavage, an enzymatic event that occurs at amino acid residues 110 and 111 on PrPC, interferes with the conversion of PrPC into the prion disease-associated isoform, PrPSc (abnormal disease-specific conformation of prion protein). This processing is seen as a positive event in terms of disease development. The study of β-cleavage has taken some surprising turns. β-Cleavage is brought about by ROS (reactive oxygen species). The C-terminal fragment produced, C2, may provide the seed for the abnormal conversion process, as it resembles in size the fragments isolated from prion-infected brains. There is, however, strong evidence that β-cleavage provides an essential process to reduce oxidative stress. β-Cleavage may act as a double-edged sword. By β-cleavage, PrPC may try to balance the ROS levels produced during prion infection, but the C2 produced may provide a PrPSc seed that maintains the prion conversion process.

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Kulikovskaya, Irina, George McClellan, Jeanne Flavigny, Lucie Carrier, and Saul Winegrad. "Effect of MyBP-C Binding to Actin on Contractility in Heart Muscle." Journal of General Physiology 122, no. 6 (November 24, 2003): 761–74. http://dx.doi.org/10.1085/jgp.200308941.

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In contrast to skeletal muscle isoforms of myosin binding protein C (MyBP-C), the cardiac isoform has 11 rather than 10 fibronectin or Ig modules (modules are identified as C0 to C10, NH2 to COOH terminus), 3 phosphorylation sites between modules C1 and C2, and 28 additional amino acids rich in proline in C5. Phosphorylation between C1 and C2 increases maximum Ca-activated force (Fmax), alters thick filament structure, and increases the probability of myosin heads on the thick filament binding to actin on the thin filament. Unphosphorylated C1C2 fragment binds to myosin, but phosphorylation inhibits the binding. MyBP-C also binds to actin. Using two types of immunoprecipitation and cosedimentation, we show that fragments of MyBP-C containing C0 bind to actin. In low concentrations C0-containing fragments bind to skinned fibers when the NH2 terminus of endogenous MyBP-C is bound to myosin, but not when MyBP-C is bound to actin. C1C2 fragments bind to skinned fibers when endogenous MyBP-C is bound to actin but not to myosin. Disruption of interactions of endogenous C0 with a high concentration of added C0C2 fragments produces the same effect on contractility as extraction of MyBP-C, namely decrease in Fmax and increase in Ca sensitivity. These results suggest that cardiac contractility can be regulated by shifting the binding of the NH2 terminus of MyBP-C between actin and myosin. This mechanism may have an effect on diastolic filling of the heart.

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Casellato, Alessandro, Silvia Rossi Paccani, Riccardo Barrile, Fleur Bossi, Laura Ciucchi, Gaia Codolo, Mariagrazia Pizza, Beatrice Aricò, and Marina de Bernard. "The C2 fragment fromNeisseria meningitidisantigen NHBA increases endothelial permeability by destabilizing adherens junctions." Cellular Microbiology 16, no. 6 (January 8, 2014): 925–37. http://dx.doi.org/10.1111/cmi.12250.

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25

Claessens, F., L. Dirckx, B. Delaey, J. L. Decourt, K. Hemschoote, B. Peeters, and W. Rombauts. "The androgen-dependent rat prostatic binding protein: comparison of the sequences in the 5′ part and upstream region of the Cl and C2 genes and analysis of their transcripts." Journal of Molecular Endocrinology 3, no. 2 (September 1989): 93–103. http://dx.doi.org/10.1677/jme.0.0030093.

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ABSTRACT The complete gene encoding the polypeptide Cl of the complex androgen-controlled prostatic binding protein was isolated from a rat genomic library. A new genomic fragment (C2B) containing only the 5′ part of a C2-related gene was also purified. The segments containing exon 1 and a large part of the adjacent sequences were analysed and compared with the corresponding region of the C2A gene which has been completely sequenced previously. The high structural similarity extending over a large part of all three genomic fragments suggests the duplication of a common ancestral gene, followed by a more recent duplication of the C2-coding region. However, since the structural similarity upstream of position − 150 between C2A and C2B abruptly disappears and no transcripts specific for the C2B region can be detected in prostate RNA, we propose that at a later stage in evolution the C2B region was disrupted and inactivated. Despite the common origin and the similar regulation of the two active genes, Cl and C2A, the only obvious conserved structural element is the homopurine stretch located at position −400, although sequence motifs resembling steroid hormone response elements are present at several locations.

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26

Ganderton, Tim, Jason W. H. Wong, Christina Schroeder, and Philip J. Hogg. "Lateral self-association of VWF involves the Cys2431-Cys2453 disulfide/dithiol in the C2 domain." Blood 118, no. 19 (November 10, 2011): 5312–18. http://dx.doi.org/10.1182/blood-2011-06-360297.

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Abstract VWF is a plasma protein that binds platelets to an injured vascular wall during thrombosis. When exposed to the shear forces found in flowing blood, VWF molecules undergo lateral self-association that results in a meshwork of VWF fibers. Fiber formation has been shown to involve thiol/disulfide exchange between VWF molecules. A C-terminal fragment of VWF was expressed in mammalian cells and examined for unpaired cysteine thiols using tandem mass spectrometry (MS). The VWF C2 domain Cys2431-Cys2453 disulfide bond was shown to be reduced in approximately 75% of the molecules. Fragments containing all 3 C domains or just the C2 domain formed monomers, dimers, and higher-order oligomers when expressed in mammalian cells. Mutagenesis studies showed that both the Cys2431-Cys2453 and nearby Cys2451-Cys2468 disulfide bonds were involved in oligomer formation. Our present findings imply that lateral VWF dimers form when a Cys2431 thiolate anion attacks the Cys2431 sulfur atom of the Cys2431-Cys2453 disulfide bond of another VWF molecule, whereas the Cys2451-Cys2468 disulfide/dithiol mediates formation of trimers and higher-order oligomers. These observations provide the basis for exploring defects in lateral VWF association in patients with unexplained hemorrhage or thrombosis.

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Spiegel, Paul Clint, Marc Jacquemin, Jean-Marie R. Saint-Remy, Barry L. Stoddard, and Kathleen P. Pratt. "Structure of a factor VIII C2 domain–immunoglobulin G4κ Fab complex: identification of an inhibitory antibody epitope on the surface of factor VIII." Blood 98, no. 1 (July 1, 2001): 13–19. http://dx.doi.org/10.1182/blood.v98.1.13.

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Abstract The development of an immune response to infused factor VIII is a complication affecting many patients with hemophilia A. Inhibitor antibodies bind to antigenic determinants on the factor VIII molecule and block its procoagulant activity. A patient-derived inhibitory immunoglobulin G4κ antibody (BO2C11) produced by an immortalized memory B-lymphocyte cell line interferes with the binding of factor VIII to phospholipid surfaces and to von Willebrand factor. The structure of a Fab fragment derived from this antibody complexed with the factor VIII C2 domain was determined at 2.0 Å resolution. The Fab interacts with solvent-exposed basic and hydrophobic side chains that form a membrane-association surface of factor VIII. This atomic resolution structure suggests a variety of amino acid substitutions in the C2 domain of factor VIII that might prevent the binding of anti-C2 inhibitor antibodies without significantly compromising the procoagulant functions of factor VIII.

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28

Engelhardt, LM, CL Raston, and AH White. "Crystal Structure of N,N,N′,N′-Tetrakis-(trimethylsilyl)ethane-1,2-diamine." Australian Journal of Chemistry 38, no. 11 (1985): 1729. http://dx.doi.org/10.1071/ch9851729.

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The title compound, [{(Me3Si)2NCH2}2], has been structurally characterized by a single-crystal X-ray structure determination at 130 K, being refined by full-matrix least-squares to a residual of 0.057 for 1244 'observed' reflections. Crystals are monoclinic, C2/c, a 21.00(2), b 9.089(8), c 11.744(9) Ǻ, β 92.31(7)°, Z 4. Molecules lie on inversion centres, but with some disorder of the methylene groups. Si -N are 1.735 Ǻ, and N-CH2 1.53(1) for the major fragment (70%). The nitrogen in the major fragment is approximately trigonal planar; Si -N- Si 124.6(3)°, Si -N-C 117.5(4), 115.5(4)°.

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29

Boretto, J. G., N. Pacher, D. Giunta, G. L. Gallucci, V. Alfie, and P. De Carli. "Comparative clinical study of locking screws versus smooth locking pegs in volar plating of distal radius fractures." Journal of Hand Surgery (European Volume) 39, no. 7 (January 8, 2014): 755–60. http://dx.doi.org/10.1177/1753193413517806.

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The present study was performed to test the null hypothesis on no difference in stability of fixation after volar plating of intra-articular distal radius fractures (AO C2-C3) with either locking smooth pegs or locking screws in a clinical setting. A retrospective evaluation included adult patients with C2-C3 AO fractures treated with a volar plate with locking smooth pegs or locking screws. Radiographic assessment was performed to evaluate extra- and intra-articular parameters in the early postoperative period and after bone union. Twenty-seven consecutive patients were included. Thirteen cases had fixation with locking screws and 14 had fixation with locking smooth pegs. Both groups had bone fragment displacement after fixation. However, there were no significant differences between the groups either in extra- or intra-articular parameters defined by Kreder et al. (1996). Our study shows that, in a clinical setting, there is no difference in stability fixation between locking screws or smooth locking pegs in C2-C3 distal radius fractures.

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30

Grue-Sørensen, Gunnar, and Ian D. Spenser. "The biosynthesis of ephedrine." Canadian Journal of Chemistry 67, no. 6 (June 1, 1989): 998–1009. http://dx.doi.org/10.1139/v89-152.

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It is shown by 13C nuclear magnetic resonance spectroscopy that the labelled C2 fragment of [2,3-13C2]pyruvic acid is transferred intact into the C-methyl group and the adjacent carbon atom of the Ephedra alkaloids, norephedrine, ephedrine, norpseudoephedrine, and pseudoephedrine, in growing plants of Ephedragerardiana. This finding serves to identify pyruvate as the elusive precursor of the aliphatic C2 terminus of the skeleton of the alkaloids. In earlier experiments with C-labelled substrates, label from [3-14C]pyruvic acid was incorporated mainly, but not exclusively, into the C-methyl group of ephedrine, and label from [2-14C]pyruvate was incorporated similarly into the carbon atom adjacent to the C-methyl group. A C6–C1 unit related to benzaldehyde or benzoic acid has long been known to generate the benzylic fragment of the carbon skeleton of the Ephedra alkaloids. It is likely that the carbon skeleton of ephedrine is generated from pyruvate and either benzaldehyde or benzoic acid, by a reaction analogous to the formation of acetoin or diacetyl from pyruvate and acetaldehyde or acetic acid, respectively. Keywords: biosynthesis of ephedrine, Ephedra alkaloids, 13C NMR spectra, ephedrine, biosynthesis of pyruvic acid, incorporation into ephedrine13C NMR spectra.

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31

Scandella, D., M. Mattingly, S. de Graaf, and CA Fulcher. "Localization of epitopes for human factor VIII inhibitor antibodies by immunoblotting and antibody neutralization." Blood 74, no. 5 (October 1, 1989): 1618–26. http://dx.doi.org/10.1182/blood.v74.5.1618.1618.

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Abstract Human factor VIII(FVIII) inhibitors are pathologic, circulating antibodies that inactivate FVIII. We have examined the location of epitopes on the FVIII protein for inhibitors from hemophilia A and nonhemophilic individuals. The inhibitors were of type I or type II in the kinetics of their inactivation of FVIII. A cDNA clone of human FVIII was used to express defined FVIII protein fragments in Escherichia coli for immunoblotting with inhibitor plasma. An epitope for 18 heavy-chain inhibitors was localized to the aminoterminal 18.3 Kd of the A2 domain. Two of these inhibitors also recognized an epitope located between A1 and A2 domains. Similarly, an epitope for 23 light- chain inhibitors was localized to the C2 domain. Weaker epitopes for 13 of the same inhibitors within the C1 and C2 domains were also observed. Four of the 23 inhibitors in addition bound strongly to the A3 domain. Most inhibitors (22 of 23) were neutralized in vitro only by the FVIII fragments to which they bound on immunoblots; however, one inhibitor that was neutralized by a fragment containing the A1 domain did not bind to it on immunoblots. Conversely, 3 of 3 inhibitors that bound to the A3 domain and 5 of 15 that bound to the A2 domain were not neutralized by the corresponding fragments. The epitope specificity of an inhibitor did not depend on its source or type. Our results show that FVIII inhibitors bind to limited areas within the heavy and light chains of FVIII. Some inhibitor plasmas contain additional antibodies that may not be inhibitory.

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32

Scandella, D., M. Mattingly, S. de Graaf, and CA Fulcher. "Localization of epitopes for human factor VIII inhibitor antibodies by immunoblotting and antibody neutralization." Blood 74, no. 5 (October 1, 1989): 1618–26. http://dx.doi.org/10.1182/blood.v74.5.1618.bloodjournal7451618.

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Human factor VIII(FVIII) inhibitors are pathologic, circulating antibodies that inactivate FVIII. We have examined the location of epitopes on the FVIII protein for inhibitors from hemophilia A and nonhemophilic individuals. The inhibitors were of type I or type II in the kinetics of their inactivation of FVIII. A cDNA clone of human FVIII was used to express defined FVIII protein fragments in Escherichia coli for immunoblotting with inhibitor plasma. An epitope for 18 heavy-chain inhibitors was localized to the aminoterminal 18.3 Kd of the A2 domain. Two of these inhibitors also recognized an epitope located between A1 and A2 domains. Similarly, an epitope for 23 light- chain inhibitors was localized to the C2 domain. Weaker epitopes for 13 of the same inhibitors within the C1 and C2 domains were also observed. Four of the 23 inhibitors in addition bound strongly to the A3 domain. Most inhibitors (22 of 23) were neutralized in vitro only by the FVIII fragments to which they bound on immunoblots; however, one inhibitor that was neutralized by a fragment containing the A1 domain did not bind to it on immunoblots. Conversely, 3 of 3 inhibitors that bound to the A3 domain and 5 of 15 that bound to the A2 domain were not neutralized by the corresponding fragments. The epitope specificity of an inhibitor did not depend on its source or type. Our results show that FVIII inhibitors bind to limited areas within the heavy and light chains of FVIII. Some inhibitor plasmas contain additional antibodies that may not be inhibitory.

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33

Clark, J. Stephen, Guang Yang, and Andrew P. Osnowski. "Synthesis of the C-18–C-34 Fragment of Amphidinolides C, C2, and C3." Organic Letters 15, no. 7 (March 25, 2013): 1464–67. http://dx.doi.org/10.1021/ol400482j.

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34

Schwäbe, Frederic V., Emanuel K. Peter, Manuel H. Taft, and Dietmar J. Manstein. "Assessment of the Contribution of a Thermodynamic and Mechanical Destabilization of Myosin-Binding Protein C Domain C2 to the Pathomechanism of Hypertrophic Cardiomyopathy-Causing Double Mutation MYBPC3Δ25bp/D389V." International Journal of Molecular Sciences 22, no. 21 (November 4, 2021): 11949. http://dx.doi.org/10.3390/ijms222111949.

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Mutations in the gene encoding cardiac myosin-binding protein-C (MyBPC), a thick filament assembly protein that stabilizes sarcomeric structure and regulates cardiac function, are a common cause for the development of hypertrophic cardiomyopathy. About 10% of carriers of the Δ25bp variant of MYBPC3, which is common in individuals from South Asia, are also carriers of the D389V variant on the same allele. Compared with noncarriers and those with MYBPC3Δ25bp alone, indicators for the development of hypertrophic cardiomyopathy occur with increased frequency in MYBPC3Δ25bp/D389V carriers. Residue D389 lies in the IgI-like C2 domain that is part of the N-terminal region of MyBPC. To probe the effects of mutation D389V on structure, thermostability, and protein–protein interactions, we produced and characterized wild-type and mutant constructs corresponding to the isolated 10 kDa C2 domain and a 52 kDa N-terminal fragment that includes subdomains C0 to C2. Our results show marked reductions in the melting temperatures of D389V mutant constructs. Interactions of construct C0–C2 D389V with the cardiac isoforms of myosin-2 and actin remain unchanged. Molecular dynamics simulations reveal changes in the stiffness and conformer dynamics of domain C2 caused by mutation D389V. Our results suggest a pathomechanism for the development of HCM based on the toxic buildup of misfolded protein in young MYBPC3Δ25bp/D389V carriers that is supplanted and enhanced by C-zone haploinsufficiency at older ages.

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35

Naito, Kiyohito, Yoichi Sugiyama, Mayuko Kinoshita, Hiroyuki Obata, Kenji Goto, Nana Nagura, Yoshiyuki Iwase, Osamu Obayashi, and Kazuo Kaneko. "Functional Outcomes in Volar-Displaced Distal Radius Fractures Patients with Marginal Rim Fragment Treated by Volar Distal Locking Plates." Journal of Hand and Microsurgery 11, no. 02 (December 28, 2018): 100–105. http://dx.doi.org/10.1055/s-0038-1675245.

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Abstract Background Treatment of volar-displaced distal radius fractures (DRF) accompanied by marginal rim fragment has recently been actively discussed. It is difficult to obtain a sufficient buttress effect on this fragment. Therefore, we actively apply a distal volar locking plate (DVLP) to fractures with this fragment. Here, we report the treatment outcomes and caveats of surgery of fractures with this fragment. Materials and Methods The subjects were 32 patients (male: 11, female: 21, and mean age: 59.4 years) with volar dislocated DRF accompanied by the marginal rim fragment treated using DVLP. The fracture type of AO classification was B3 in 6 patients, C1 in 12, C2 in 6, and C3 in 8. Results The mean duration of follow-up was 13.8 (12–30) months. The plate could be covered with the pronator quadratus muscle in surgery in all patients. On the final follow-up, visual analog scale score was 1.4/10, quick disabilities of the arm, shoulder, and hand score was 9.2/100, and the Mayo wrist score was 93.7/100. No complication was observed in the soft tissue, such as the nerves and flexor tendons. Conclusion The factor determining retention of the reduction position of the marginal rim fragment is a sufficient buttress effect, and DVLP is a useful implant in terms of this point.

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36

Krishnan, Vengadesan, Yuanyuan Xu, Kevin Macon, John E. Volanakis, and Sthanam V. L. Narayana. "The structure of C2b, a fragment of complement component C2 produced during C3 convertase formation." Acta Crystallographica Section D Biological Crystallography 65, no. 3 (February 20, 2009): 266–74. http://dx.doi.org/10.1107/s0907444909000389.

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37

Ferrié, Laurent, and Bruno Figadère. "Efficient Synthesis of the C(1)−C(9) Fragment of Amphidinolides C, C2, and F." Organic Letters 12, no. 21 (November 5, 2010): 4976–79. http://dx.doi.org/10.1021/ol1021228.

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38

Dutta, T. K., J. C. Vites, and T. P. Fehlner. "The mechanism of the hydrogenation-dehydrogenation of a C2 fragment on a triiron cluster site." Organometallics 5, no. 2 (February 1986): 385–86. http://dx.doi.org/10.1021/om00133a033.

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39

Clark, J. Stephen, Guang Yang, and Andrew P. Osnowski. "Synthesis of the C-1–C-17 Fragment of Amphidinolides C, C2, C3, and F." Organic Letters 15, no. 7 (March 25, 2013): 1460–63. http://dx.doi.org/10.1021/ol4004838.

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40

Al-Adiwish, Wedad M., and Wedad M. Barag. "Synthesis and Study of the Crystal Structure of 2-[(Dipyrrolidin-1-yl) methylene] malononitrile." Al-Mukhtar Journal of Sciences 37, no. 2 (June 30, 2022): 105–12. http://dx.doi.org/10.54172/mjsc.v37i2.383.

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This study aims to synthesis 2-[(dipyrrolidin-1-yl)methylene] malononitrile 2 and identify its crystal structure by X-ray diffraction analysis. 2-[(dipyrrolidin-1-yl)methylene] malononitrile was prepared by a direct displacement of the methylthio group (SMe) in the 2-[bis(methylthio)methylene] malononitrile 1 with pyrrolidine as cyclic secondary amine by conjugating addition-elimination reaction under reflux conditions for two hours. The compound was obtained in high yield (80%). The structure of compound 2-[(dipyrrolidin-1-yl)methylene] malononitrile2 was identified by performing X-ray diffraction analysis. Suitable crystals of compound 2 were grown by slow evaporation of methanol solution of the compound. The compound 2 crystallized in an orthorhombic crystal system with a space group of Pbcn. In the title compound, the two cyanide groups and the two pyrrolidine rings adopted trans configurations across the C2=C3 bond. The bond lengths and angles of the two pyrrolidinyl rings in the compound are within the normal range. The maximum deviation of N5/C2/C3/C4/N5a/C4a is 0.002(1) around C4, and no deviation has been recorded for the fragment N1/N1a/C2/C3 (0.000 (1)°). The dihedral angle between the pyrrolidine ring and N1/N1a/C2/C3 is 33.06(8)°, and the dihedral angle between the pyrrolidine ring and N5/C2/C3/C4/N5a/C4a is 50.57(7)°. The crystal packing is stabilized by two intermolecular and one intramolecular C---H…N hydrogen bonds, which form a one-dimensional polymeric chain along the axis.

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41

Jarvis, Audrey W. "Analysis of phage resistance mechanisms encoded by lactococcal plasmid pAJ2074." Canadian Journal of Microbiology 39, no. 2 (February 1, 1993): 252–58. http://dx.doi.org/10.1139/m93-035.

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Lactococcal plasmid pAJ2074 is a 74-kb plasmid that confers phage resistance at 30 °C against all lactococcal phages with prolate heads (referred to as prolate phage), and most small lactococcal phages with isometric heads (referred to as small isometric phage) that have been tested. The presence of pAJ2074 had no effect on phage adsorption or injection of phage DNA. Replication of prolate phage c2 DNA could not be detected in bacterial cells containing the plasmid up to 60 min after phage infection, whereas phage c2 DNA replication could be demonstrated at 20 min in the control strain. With pAJ2074 present there was no detectable growth of phage c2 and an 87% reduction in burst size for the small isometric phage sk1. Infective centres were reduced in the presence of pAJ2074 by 99% for phage c2 and by 93% for phage sk1. Plasmid pAJ2074 differed from pTR2030, in that the major effect of pAJ2074 was on prolate phage c2, rather than on the small isometric phage sk1, and no restriction and modification system could be detected. In addition, no DNA homology was detected between pAJ2074 and pTRK67 (derived from pTR2030). A recombinant plasmid pAJ88 containing an 8.4-kb insert from pAJ2074 conferred an intermediate level of phage resistance. The DNA region that encoded reduced phage sensitivity was further defined by the subcloning of a 5.6-kb EcoRV fragment that conferred resistance similar to pAJ88. The possibility of two phage-resistance mechanisms being encoded by pAJ2074 is discussed.Key words: phage resistance, lactococcal phages, lactococcal plasmids, lactococci.

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42

Montaville, Pierre, Christine Schlicker, Andrei Leonov, Markus Zweckstetter, George M. Sheldrick, and Stefan Becker. "The C2A-C2B Linker Defines the High Affinity Ca2+ Binding Mode of Rabphilin-3A." Journal of Biological Chemistry 282, no. 7 (December 13, 2006): 5015–25. http://dx.doi.org/10.1074/jbc.m606746200.

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The Ca2+ binding properties of C2 domains are essential for the function of their host proteins. We present here the first crystal structures showing an unexpected Ca2+ binding mode of the C2B domain of rabphilin-3A in atomic detail. Acidic residues from the linker region between the C2A and C2B domains of rabphilin-3A interact with the Ca2+-binding region of the C2B domain. Because of these interactions, the coordination sphere of the two bound Ca2+ ions is almost complete. Mutation of these acidic residues to alanine resulted in a 10-fold decrease in the intrinsic Ca2+ binding affinity of the C2B domain. Using NMR spectroscopy, we show that this interaction occurred only in the Ca2+-bound state of the C2B domain. In addition, this Ca2+ binding mode was maintained in the C2 domain tandem fragment. In NMR-based liposome binding assays, the linker was not released upon phospholipid binding. Therefore, this unprecedented Ca2+ binding mode not only shows how a C2 domain increases its intrinsic Ca2+ affinity, but also provides the structural base for an atypical protein-Ca2+-phospholipid binding mode of rabphilin-3A.

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43

Messer, Amanda S., Barbara Ulmasov, Yogesh Kumar, Kanagasabai Vadivel, Degang Zhong, Philip Fay, and S. Paul Bajaj. "Epitope Mapping of a Monoclonal Antibody to Factor VIII That Inhibits Factor IXa:Factor VIIIa Interaction and Thrombin Activation of Factor VIII." Blood 118, no. 21 (November 18, 2011): 1177. http://dx.doi.org/10.1182/blood.v118.21.1177.1177.

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Abstract Abstract 1177 Factor VIII (FVIII) circulates in plasma as a noncovalent heterodimer consisting of a heavy chain (HC, A1-a1-A2-a2-B domains) and a light chain (LC, a3-A3-C1-C2 domains) in a noncovalent complex with von Willebrand factor (wVF). Thrombin (IIa) cleaves FVIII between the A1-a1/A2 domains at Arg372, A2-a2/B domains at Arg740 and B-a3/A3 domains at Arg1689 generating FVIIIa that consists of an A1-a1/A2-a2/A3-C1-C2 heterotrimer. FVIIIa increases the efficiency of Factor IXa (FIXa) catalyzed activation of Factor X (FX) in a Ca2+ and phospholipid (PL) dependent manner. The A3-C1-C2 segment of FVIIIa plays an important role in FIXa:FVIIIa interaction. Here, we describe a series of experiments to map the epitope of a monoclonal antibody (mAb) that is reported to inhibit FVIII clotting activity in a one stage clotting assay (Brown et al; J Lab Clin Med, 101: 793–805, 1983). The binding of mAb to FVIII, B-domain deleted FVIII and isolated LC was assessed using surface plasmon resonance. In these experiments, mAb captured on a protein A/G coupled CM5 sensor chip served as the ligand, and FVIII and its isolated fragments served as the analytes. The Kd of binding of LC (∼40 nM) was similar to FVIII and the B-domain deleted FVIII. No binding was observed for isolated A1 and A2 domains. Further, in plasma based inhibition assays, the Kd of binding of mAb to FVIII-vWF complex and to FVIII was ∼30 nM. This suggests that the mAb epitope does not significantly overlap with the vWF binding site in the acidic a3 region of LC. Western blot analysis confirmed that the mAb is specific for the LC of FVIII. Moreover, IIa-cleaved LC starting at residue 1690 gave only a weak signal and FXa-cleaved LC starting at residue 1721 did not react with the mAb in Western blots. These data suggest that the epitope for this mAb spans the IIa-cleavage site in the LC. Consistent with these observations, the A3-C1-C2 fragment but not the C1-C2 fragment expressed in COS cells reacted with the mAb. To further define a part of the epitope in the IIa-cleaved LC, twelve A3 domain deletion fragments were constructed and expressed in E. coli. Western blot analysis of these fragments restricted the partial epitope to 1690–1710 residues of the IIa-cleaved LC. In additional experiments, the mAb did not inhibit mouse, rabbit or canine plasma FVIII in a one stage clotting assay. It did however inhibit porcine plasma FVIII with ∼40 nM Kd, sheep plasma FVIII with ∼ 68 nM Kd, and bovine plasma FVIII with ∼300 nM Kd. Analysis of the sequence alignment of residues 1680 to 1710 of FVIII from each species indicated that residues 1681 to 1694 of human FVIII most likely constitute the epitope of this mAb. The dissimilarity and the charge differences in amino acids suggest that residues Asp1681, Glu1684, Asn1685, and Ser1687 on the N terminal side and Lys1693 on the C terminal side of the IIa-cleavage site Arg1689-Ser1690 may be important for this epitope. Fluorescence energy transfer (FRET) experiments indicated that the mAb inhibits FIXa interaction with the IIa-cleaved LC consisting of A3-C1-C2 domains. In these experiments, A3-C1-C2 subunit was labeled with acrylodan (fluorescence donor) and FIXa was labeled with fluorescein-Phe-Phe-Arg-chloromethylketone (fluorescence acceptor). In the presence of FIXa, the acrylodan fluorescence was quenched indicating a biomolecular complex formation. Addition of 1.2 μM mAb abolished the acrylodan fluorescence quenching suggesting inhibition of the FIXa:LC interaction. Notably, the mAb did not inhibit activation of FX by FIXa/Ca2+/PL and FXa-cleaved FVIIIa (instead of IIa-cleaved FVIIIa). This suggests that the mAb inhibits FIXa:LC interaction by a steric hindrance and not by a direct blockage of the FIXa:LC interactive sites. In summary, the mAb inhibits clotting by preventing FVIII activation by IIa. The epitope of the mAb appears to be restricted to residues 1681–1694 of FVIII. Notably, in some of the hemophilia A patients, the epitope of the inhibitory antibodies is confined to the IIa-cleavage site including the a3 acidic domain of LC. To locate the epitope for such antibodies, one of the approaches used was to construct porcine and human FVIII hybrids. Our strategy may represent a simplified approach to locate the epitope of similar antibodies in hemophilia A patients. Such antibodies may bind strongly to LC and weakly to IIa-cleaved LC. Further, these antibodies may not bind to FXa-cleaved LC or A1/A2 subunits. Disclosures: No relevant conflicts of interest to declare.

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44

Gilbert, R., M. G. Kelly, T. Mikawa, and D. A. Fischman. "The carboxyl terminus of myosin binding protein C (MyBP-C, C-protein) specifies incorporation into the A-band of striated muscle." Journal of Cell Science 109, no. 1 (January 1, 1996): 101–11. http://dx.doi.org/10.1242/jcs.109.1.101.

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Myosin binding protein-C (MyBP-C), also known as C-protein, is a major constituent of the thick filaments of vertebrate striated muscles. The protein, approximately 130 kDa, consists of a series of 10 globular motifs (numbered I to X) each of approximately 90–100 amino acids, bearing resemblance to the C2-set of immunoglobins (Ig C2) and to the fibronectin type III (FnIII) motifs. Using pure preparations of myosin and MyBP-C, it has been demonstrated that the major myosin binding domain of MyBP-C resides within the C-terminal Ig C2 motif (motif X). However, in the context of the in vivo thick filament, it is uncertain if the latter domain is sufficient to target MyBP-C correctly to the A-band or if other regions of the molecule are required for this process. To answer this question, cultures of skeletal muscle myoblasts were transfected with expression plasmids encoding seven truncation mutants of MyBP-C, and their targeting to the A-band investigated by immunofluorescence microscopy. To distinguish the recombinant proteins from endogenous MyBP-C, a myc epitope was inserted at each amino terminus. Recombinant MyBP-C exhibited an identical distribution in the sarcomere to that of native MyBP-C; i.e. it was found exclusively in the C-zone of the A-band. A mutant encoding the C-terminal 372 amino acids, but lacking motifs I-VI (termed delta 1–6), also targeted correctly to the A-band. This fragment, which is composed of two Ig C2 and two FnIII motifs, was the minimal protein fragment required for correct A-band incorporation. Larger amino-terminal deletions or deletion of motif X, the myosin binding domain, abolished all localization to the A-band. One construct (delta 10) lacking only motif X strongly inhibited myofibril assembly. We conclude that the myosin binding domain of MyBP-C, although essential, is not sufficient for correct incorporation into the A-band and that motifs VII to IX are required for this process. The data suggest a topological model in which MyBP-C is associated with the thick filament through its C terminus.

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El-Shair, Sahar, Mohammad Al Shhab, Khaled Zayed, Moaath Alsmady, and Malek Zihlif. "Association Between CYP3A4 and CYP3A5 Genotypes and Cyclosporine's Blood Levels and Doses among Jordanian Kidney Transplanted Patients." Current Drug Metabolism 20, no. 8 (September 24, 2019): 682–94. http://dx.doi.org/10.2174/1389200220666190806141825.

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Background: Cyclosporine is used as an immunosuppressive agent in kidney transplantation. It has a narrow therapeutic window. Cyclosporine is predominantly metabolized by CYP3A4 and CYP3A5. The most common Single Nucleotide Polymorphisms (SNPs) affecting cyclosporine metabolism (CYP3A4*1B, CYP3A4*1G, CYP3A4*22 and CYP3A5*3) were investigated among Jordanian kidney transplanted patients to find out the genotypes and allele frequencies of these SNPs. Additionally, this study investigated whether genotypes of CYP3A4 and CYP3A5 affect C2 blood levels, dosing of cyclosporine and the prevalence of acute rejection. Methods: Blood samples of 109 adult patients taking cyclosporine as their primary immunosuppressant for kidney transplantation were collected from the Prince Hamzah Hospital, Amman, Jordan. Patients’ first C2 blood levels and their first two given doses were collected. Patients were genotyped for the four SNPs using Polymerase Chain Reaction- restriction Fragment Length Polymorphism (PCR-RFLP) assay method. Results: Allele frequencies among Jordanian patients for CYP3A4*1B, CYP3A4*1G, CYP3A4*22 and CYP3A5*3 were 0.037, 0.399, 0.037 and 0.271, respectively. There was a significant association between CYP3A4*22 and mean difference in the second and first given doses (P=0.034). There was a big difference between CYP3A4*22 and the mean of the first C2 blood levels (P=0.063). Conclusion: There was a strong association between CYP3A4*22 and the mean difference between the second and first given doses. There was a trend of significant difference between the mean of the first C2 blood levels among heterozygous CYP3A4*22 patients. Pharmacogenomics may hold promise in assisting the prediction of the best cyclosporine dose and C2 blood level among Jordanian kidney transplant patients.

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Lopez, Marc, Mustapha Aoubala, François Jordier, Daniel Isnardon, Sophie Gomez, and Patrice Dubreuil. "The Human Poliovirus Receptor Related 2 Protein Is a New Hematopoietic/Endothelial Homophilic Adhesion Molecule." Blood 92, no. 12 (December 15, 1998): 4602–11. http://dx.doi.org/10.1182/blood.v92.12.4602.424k21_4602_4611.

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We have recently described Poliovirus Receptor Related 2 (PRR2), a new cell surface molecule homologous to the poliovirus receptor (PVR/CD155). Both molecules are transmembrane glycoproteins belonging to the Ig superfamily (IgSF). They contain 3 Ig domains of V, C2, and C2 types in their extracellular regions that share 51% aa identity. The PRR2 gene encodes two mRNA isoforms of 3.0 kb (hPRR2 [short form]) and 4.4 kb (hPRR2δ [long form]), both widely expressed in human tissues, including hematopoietic cells. To further characterize PRR2 expression during hematopoiesis and to analyze its function, we have developed a monoclonal antibody (MoAb) directed against its extracellular region (R2.477). PRR2 was expressed in 96% of the CD34+, 88% of the CD33+, and 95% of the CD14+ hematopoietic lineages and faintly in the CD41 compartment. Ectopic expression of both PRR2 cDNAs induced marked cell aggregation. A soluble chimeric receptor construct with the Fc fragment of human IgG1 (PRR2-Fc) as well as a fab fragment of the anti-PRR2 MoAb (R2.477) inhibit aggregation. PRR2-Fc binds specifically to PRR2-expressing cells. These results suggest that PRR2 is a homophilic adhesion receptor. PRR2 was also expressed at the surface of endothelial cells at the intercellular junctions of adjacent cells but not at the free cellular edges. Homophilic interactions are associated with dimerization of isoforms of PRR2 and lead to the tyrosine phosphorylation of PRR2δ. Altogether, these results suggest that homophilic properties of PRR2 could participate to the regulation of hematopoietic/endothelial cell functions.

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Emond, Eric, Eric Dion, Shirley A. Walker, Ebenezer R. Vedamuthu, Jeffery K. Kondo, and Sylvain Moineau. "AbiQ, an Abortive Infection Mechanism fromLactococcus lactis." Applied and Environmental Microbiology 64, no. 12 (December 1, 1998): 4748–56. http://dx.doi.org/10.1128/aem.64.12.4748-4756.1998.

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ABSTRACT Lactococcus lactis W-37 is highly resistant to phage infection. The cryptic plasmids from this strain were coelectroporated, along with the shuttle vector pSA3, into the plasmid-free host L. lactis LM0230. In addition to pSA3, erythromycin- and phage-resistant isolates carried pSRQ900, an 11-kb plasmid fromL. lactis W-37. This plasmid made the host bacteria highly resistant (efficiency of plaquing <10−8) to c2- and 936-like phages. pSRQ900 did not confer any resistance to phages of the P335 species. Adsorption, cell survival, and endonucleolytic activity assays showed that pSRQ900 encodes an abortive infection mechanism. The phage resistance mechanism is limited to a 2.2-kbEcoRV/BclI fragment. Sequence analysis of this fragment revealed a complete open reading frame (abiQ), which encodes a putative protein of 183 amino acids. A frameshift mutation within abiQ completely abolished the resistant phenotype. The predicted peptide has a high content of positively charged residues (pI = 10.5) and is, in all likelihood, a cytosolic protein. AbiQ has no homology to known or deduced proteins in the databases. DNA replication assays showed that phage c21 (c2-like) and phage p2 (936-like) can still replicate in cells harboring AbiQ. However, phage DNA accumulated in its concatenated form in the infected AbiQ+ cells, whereas the AbiQ− cells contained processed (mature) phage DNA in addition to the concatenated form. The production of the major capsid protein of phage c21 was not hindered in the cells harboring AbiQ.

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Kensler, Robert W., Justin F. Shaffer, and Samantha P. Harris. "Binding of the N-terminal fragment C0–C2 of cardiac MyBP-C to cardiac F-actin." Journal of Structural Biology 174, no. 1 (April 2011): 44–51. http://dx.doi.org/10.1016/j.jsb.2010.12.003.

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Yadav, Jhillu Singh, Samala Jaya Prakash, and Yarrapothu Gangadhar. "General strategy towards chiral methylene bis-pyrans: synthesis of the C2–C16 fragment of phorboxazole A." Tetrahedron: Asymmetry 16, no. 16 (August 2005): 2722–28. http://dx.doi.org/10.1016/j.tetasy.2005.07.001.

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Kensler, Robert W., Justin F. Shaffer, and Samantha P. Harris. "Binding of the N-Terminal Fragment C0-C2 of Cardiac MyBP-C to Cardiac F-Actin." Biophysical Journal 98, no. 3 (January 2010): 554a. http://dx.doi.org/10.1016/j.bpj.2009.12.2998.

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Journal articles on the topic 'C2 fragment'

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