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Journal articles on the topic 'Hélice polyproline de type II'

Author: Grafiati

Published: 30 November 2024

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1

Zagrovic, B., J. Lipfert, E. J. Sorin, I. S. Millett, W. F. van Gunsteren, S. Doniach, and V. S. Pande. "Unusual compactness of a polyproline type II structure." Proceedings of the National Academy of Sciences 102, no. 33 (August 5, 2005): 11698–703. http://dx.doi.org/10.1073/pnas.0409693102.

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2

van Holst, G. J., S. R. Martin, A. K. Allen, D. Ashford, N. N. Desai, and A. Neuberger. "Protein conformation of potato (Solanum tuberosum) lectin determined by circular dichroism." Biochemical Journal 233, no. 3 (February 1, 1986): 731–36. http://dx.doi.org/10.1042/bj2330731.

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The structure of potato (Solanum tuberosum) lectin, which is a hydroxyproline-rich glycoprotein, has been investigated by circular dichroism. The spectra of the native lectin, and of the oxidized, reduced and carboxymethylated and deglycosylated derivatives were examined, as was a hydroxyproline-rich glycopeptide and its deglycosylated derivative. It is concluded that the lectin contains about 35% polyproline II conformation, 34% type II beta-turn and 31% irregular conformation. No indications were found for the presence of alpha-helix or beta-sheet conformations. The polyproline II conformation is heat-stable, but is markedly destabilized by deglycosylation. The type II beta-turn is destabilized by cleavage of disulphide bonds.

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3

Lam, Sik Lok, and Victor L. Hsu. "NMR identification of left-handed polyproline type II helices." Biopolymers 69, no. 2 (June 2003): 270–81. http://dx.doi.org/10.1002/bip.10354.

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4

Kubyshkin, Vladimir, and Nediljko Budisa. "Construction of a polyproline structure with hydrophobic exterior using octahydroindole-2-carboxylic acid." Organic & Biomolecular Chemistry 15, no. 3 (2017): 619–27. http://dx.doi.org/10.1039/c6ob02306a.

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5

Song, Jikui, Jered V. McGivern, Karl W. Nichols, John L. Markley, and Michael D. Sheets. "Structural basis for RNA recognition by a type II poly(A)-binding protein." Proceedings of the National Academy of Sciences 105, no. 40 (September 29, 2008): 15317–22. http://dx.doi.org/10.1073/pnas.0801274105.

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We identified a functional domain (XlePABP2-TRP) of Xenopus laevis embryonic type II poly(A)-binding protein (XlePABP2). The NMR structure of XlePABP2-TRP revealed that the protein is a homodimer formed by the antiparallel association of β-strands from the single RNA recognition motif (RRM) domain of each subunit. In each subunit of the homodimer, the canonical RNA recognition site is occluded by a polyproline motif. Upon poly(A) binding, XlePABP2-TRP undergoes a dimer-monomer transition that removes the polyproline motif from the RNA recognition site and allows it to be replaced by the adenosine nucleotides of poly(A). Our results provide high-resolution structural information concerning type II PABPs and an example of a single RRM domain protein that transitions from a homodimer to a monomer upon RNA binding. These findings advance our understanding of RRM domain regulation, poly(A) recognition, and are relevant to understanding how type II PABPs function in mRNA processing and human disease.

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6

Vlasov, Peter K., Anna V. Vlasova, Vladimir G. Tumanyan, and Natalia G. Esipova. "A tetrapeptide-based method for polyproline II-type secondary structure prediction." Proteins: Structure, Function, and Bioinformatics 61, no. 4 (October 17, 2005): 763–68. http://dx.doi.org/10.1002/prot.20670.

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7

Doose, S., H. Neuweiler, H. Barsch, and M. Sauer. "Probing polyproline structure and dynamics by photoinduced electron transfer provides evidence for deviations from a regular polyproline type II helix." Proceedings of the National Academy of Sciences 104, no. 44 (October 23, 2007): 17400–17405. http://dx.doi.org/10.1073/pnas.0705605104.

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8

Vlasov, P. K., A. V. Budzko, M. A. Rubin, V. G. Tumanyan, A. A. Makarov, and N. G. Esipova. "Left-handed helix of polyproline ii type in linker regions of DNA-binding proteins." Biophysics 53, no. 6 (December 2008): 663–64. http://dx.doi.org/10.1134/s0006350908060353.

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9

Srinivasan, Mythily, and A. Keith Dunker. "Proline Rich Motifs as Drug Targets in Immune Mediated Disorders." International Journal of Peptides 2012 (May 16, 2012): 1–14. http://dx.doi.org/10.1155/2012/634769.

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The current version of the human immunome network consists of nearly 1400 interactions involving approximately 600 proteins. Intermolecular interactions mediated by proline-rich motifs (PRMs) are observed in many facets of the immune response. The proline-rich regions are known to preferentially adopt a polyproline type II helical conformation, an extended structure that facilitates transient intermolecular interactions such as signal transduction, antigen recognition, cell-cell communication and cytoskeletal organization. The propensity of both the side chain and the backbone carbonyls of the polyproline type II helix to participate in the interface interaction makes it an excellent recognition motif. An advantage of such distinct chemical features is that the interactions can be discriminatory even in the absence of high affinities. Indeed, the immune response is mediated by well-orchestrated low-affinity short-duration intermolecular interactions. The proline-rich regions are predominantly localized in the solvent-exposed regions such as the loops, intrinsically disordered regions, or between domains that constitute the intermolecular interface. Peptide mimics of the PRM have been suggested as potential antagonists of intermolecular interactions. In this paper, we discuss novel PRM-mediated interactions in the human immunome that potentially serve as attractive targets for immunomodulation and drug development for inflammatory and autoimmune pathologies.

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10

Mazuryk, Jarosław, Izabela Puchalska, Kamil Koziński, Magdalena J. Ślusarz, Jarosław Ruczyński, Piotr Rekowski, Piotr Rogujski, et al. "PTD4 Peptide Increases Neural Viability in an In Vitro Model of Acute Ischemic Stroke." International Journal of Molecular Sciences 22, no. 11 (June 4, 2021): 6086. http://dx.doi.org/10.3390/ijms22116086.

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Ischemic stroke is a disturbance in cerebral blood flow caused by brain tissue ischemia and hypoxia. We optimized a multifactorial in vitro model of acute ischemic stroke using rat primary neural cultures. This model was exploited to investigate the pro-viable activity of cell-penetrating peptides: arginine-rich Tat(49–57)-NH2 (R49KKRRQRRR57-amide) and its less basic analogue, PTD4 (Y47ARAAARQARA57-amide). Our model included glucose deprivation, oxidative stress, lactic acidosis, and excitotoxicity. Neurotoxicity of these peptides was excluded below a concentration of 50 μm, and PTD4-induced pro-survival was more pronounced. Circular dichroism spectroscopy and molecular dynamics (MD) calculations proved potential contribution of the peptide conformational properties to neuroprotection: in MD, Tat(49–57)-NH2 adopted a random coil and polyproline type II helical structure, whereas PTD4 adopted a helical structure. In an aqueous environment, the peptides mostly adopted a random coil conformation (PTD4) or a polyproline type II helical (Tat(49–57)-NH2) structure. In 30% TFE, PTD4 showed a tendency to adopt a helical structure. Overall, the pro-viable activity of PTD4 was not correlated with the arginine content but rather with the peptide’s ability to adopt a helical structure in the membrane-mimicking environment, which enhances its cell membrane permeability. PTD4 may act as a leader sequence in novel drugs for the treatment of acute ischemic stroke.

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11

Siermala, Markku, Martti Juhola, and Mauno Vihinen. "On preprocessing of protein sequences for neural network prediction of polyproline type II secondary structures." Computers in Biology and Medicine 31, no. 5 (September 2001): 385–98. http://dx.doi.org/10.1016/s0010-4825(01)00013-0.

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12

Schweitzer-Stenner, Reinhard, Bridget Milorey, and Harald Schwalbe. "Randomizing of Oligopeptide Conformations by Nearest Neighbor Interactions between Amino Acid Residues." Biomolecules 12, no. 5 (May 11, 2022): 684. http://dx.doi.org/10.3390/biom12050684.

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Flory’s random coil model assumes that conformational fluctuations of amino acid residues in unfolded poly(oligo)peptides and proteins are uncorrelated (isolated pair hypothesis, IPH). This implies that conformational energies, entropies and solvation free energies are all additive. Nearly 25 years ago, analyses of coil libraries cast some doubt on this notion, in that they revealed that aromatic, but also β-branched side chains, could change the 3J(HNHCα) coupling of their neighbors. Since then, multiple bioinformatical, computational and experimental studies have revealed that conformational propensities of amino acids in unfolded peptides and proteins depend on their nearest neighbors. We used recently reported and newly obtained Ramachandran plots of tetra- and pentapeptides with non-terminal homo- and heterosequences of amino acid residues to quantitatively determine nearest neighbor coupling between them with a Ising type model. Results reveal that, depending on the choice of amino acid residue pairs, nearest neighbor interactions either stabilize or destabilize pairs of polyproline II and β-strand conformations. This leads to a redistribution of population between these conformations and a reduction in conformational entropy. Interactions between residues in polyproline II and turn(helix)-forming conformations seem to be cooperative in most cases, but the respective interaction parameters are subject to large statistical errors.

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13

Feng, Chuang, Zhen Wang, Guokun Li, Xiaohan Yang, Nannan Wu, and Lei Wang. "BERT-PPII: The Polyproline Type II Helix Structure Prediction Model Based on BERT and Multichannel CNN." BioMed Research International 2022 (August 24, 2022): 1–14. http://dx.doi.org/10.1155/2022/9015123.

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Predicting the polyproline type II (PPII) helix structure is crucial important in many research areas, such as the protein folding mechanisms, the drug targets, and the protein functions. However, many existing PPII helix prediction algorithms encode the protein sequence information in a single way, which causes the insufficient learning of protein sequence feature information. To improve the protein sequence encoding performance, this paper proposes a BERT-based PPII helix structure prediction algorithm (BERT-PPII), which learns the protein sequence information based on the BERT model. The BERT model’s CLS vector can fairly fuse sample’s each amino acid residue information. Thus, we utilize the CLS vector as the global feature to represent the sample’s global contextual information. As the interactions among the protein chains’ local amino acid residues have an important influence on the formation of PPII helix, we utilize the CNN to extract local amino acid residues’ features which can further enhance the information expression of protein sequence samples. In this paper, we fuse the CLS vectors with CNN local features to improve the performance of predicting PPII structure. Compared to the state-of-the-art PPIIPRED method, the experimental results on the unbalanced dataset show that the proposed method improves the accuracy value by 1% on the strict dataset and 2% on the less strict dataset. Correspondingly, the results on the balanced dataset show that the AUCs of the proposed method are 0.826 on the strict dataset and 0.785 on less strict datasets, respectively. For the independent test set, the proposed method has the AUC value of 0.827 on the strict dataset and 0.783 on the less strict dataset. The above experimental results have proved that the proposed BERT-PPII method can achieve a superior performance of predicting the PPII helix.

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14

Pilpel, Yair, Oren Bogin, Vlad Brumfeld, and Ziv Reich. "Polyproline Type II Conformation in the C-Terminal Domain of the Nuclear Pore Complex Protein gp210†." Biochemistry 42, no. 12 (April 2003): 3519–26. http://dx.doi.org/10.1021/bi0266176.

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15

Cutini, Michele, Marta Corno, Dominique Costa, and Piero Ugliengo. "How Does Collagen Adsorb on Hydroxyapatite? Insights From Ab Initio Simulations on a Polyproline Type II Model." Journal of Physical Chemistry C 123, no. 13 (December 18, 2017): 7540–50. http://dx.doi.org/10.1021/acs.jpcc.7b10013.

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16

Perczel, András, Ödön Farkas, Imre G. Csizmadia, and Attila G. Császar. "Peptide models XX. Aromatic side-chain–backbone interaction in phenylalanine-containing diamide model system. A systematic search for the identification of all the ab initio conformers of N-formyl-L-phenylalanine-amide." Canadian Journal of Chemistry 75, no. 8 (August 1, 1997): 1120–30. http://dx.doi.org/10.1139/v97-134.

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Phenylalanine is the simplest among the four natural amino acid residues that have aromatic side chains. The ab initio conformational analysis performed at the RHF/3-21G level on a phenylalanine-containing diamide model system (N-Formyl-L-Phe-NH2) revealed 19 different structures. Single-point energy calculations were performed using RHF/6-31+G* and DFT(B3LYP)/6-311++G** levels for all conformers. The inverse (γL) and the normal (γD) gamma turn, the extended (βL), the left-handed helical [Formula: see text], and the inverse polyproline II [Formula: see text] backbone conformers each have three (g+, a, and g−) side-chain (χ1,) rotamers. The [Formula: see text] and the [Formula: see text] type main-chain conformers have only two side-chain orientations, respectively. No minima have been found for the conformational building unit of the right-handed helical [Formula: see text] and for the polyproline II [Formula: see text] structures. The present ab initio conformational analysis for For-L-Phe-NH2 is a unique example in which a systematic and complete conformational set was established for a diamide system with an aromatic side chain. Analytic vibrational frequency calculations were established for all stationary points found as minima on the potential energy surface. These data may be used in the future as reference conformers in more detailed vibrational and (or) chemical shielding calculations or during the structural analysis of peptides and proteins by X-ray or NMR techniques. Keywords: ab initio peptide conformers, all RHF/3-21G structures of For-L-Phe-NH2, backbone – side-chain interaction in phenylalanine-containing peptide models.

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17

Siermala, M., M. Juhola, and M. Vihinen. "On Postprocessing of Neural Network Prediction of Polyproline Type II Secondary Structures: Network Spectrum, Response Analysis, and Scattering." Neural Computing & Applications 11, no. 3-4 (June 1, 2003): 238–43. http://dx.doi.org/10.1007/s00521-003-0360-5.

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18

Reuter, Cédric, Robert Opitz, Arne Soicke, Stephan Dohmen, Matthias Barone, Slim Chiha, Marco Tobias Klein, Jörg-Martin Neudörfl, Ronald Kühne, and Hans-Günther Schmalz. "Design and Stereoselective Synthesis of ProM-2: A Spirocyclic Diproline Mimetic with Polyproline Type II (PPII) Helix Conformation." Chemistry - A European Journal 21, no. 23 (April 23, 2015): 8464–70. http://dx.doi.org/10.1002/chem.201406493.

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19

Renugopalakrishnan, V., L. A. Carreira, T. W. Collette, J. C. Dobbs, G. Chandraksasan, and R. C. Lord. "Non-Uniform Triple Helical Structure in Chick Skin Type I Collagen on Thermal Denaturation: Raman Spectroscopic Study." Zeitschrift für Naturforschung C 53, no. 5-6 (June 1, 1998): 383–88. http://dx.doi.org/10.1515/znc-1998-5-613.

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The individual chains in the triple helix of collagen occur in a conformation related to polyproline II because of the presence of large number of imino peptide bonds. However, these residues are not evenly distributed in the collagen molecule which also contains many non-imino residues. These non-imino regions of collagen may be expected to show preference for other than triple helical conformations. The appearance of several Raman bands in solution phase at 65 °C raises the possibility of non-uniform triple helical structure in collagen. Raman spectroscopic studies on collagen in the solid state and in solution at a temperature greater than its denaturation temperature, reported here suggest that denatured collagen may exhibit an ensemble of conformational states with yet unknown implications to the biochemical interactions of this important protein component of connective tissues.

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20

Pazderková, Markéta, Eva Kočišová, Tomáš Pazderka, Petr Maloň, Vladimír Kopecký Jr., Lenka Monincová, Václav Čeřovský, and Lucie Bednárová. "Antimicrobial Peptide from the Eusocial BeeHalictus sexcinctusInteracting with Model Membranes." Spectroscopy: An International Journal 27 (2012): 497–502. http://dx.doi.org/10.1155/2012/840956.

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Halictine-1 (Hal-1)—a linear antibacterial dodecapeptide isolated from the venom of the eusocial beeHalictus sexcinctus—has been subjected to a detailed spectroscopic study including circular dichroism, fluorescence, and vibrational spectroscopy. We investigated Hal-1 ability to adopt an amphipathicα-helical structure upon interaction with model lipid-based bacterial membranes (phosphatidylcholine/phosphatidylglycerol-based large unilamellar vesicles and sodium dodecylsulfate micelles) and helix inducing components (trifluoroethanol). It was found that Hal-1 responds sensitively to the composition of the membrane model and to the peptide/lipid ratio. The amphipathic nature of the helical Hal-1 seems to favour flat charged surfaces of the model lipid particles over the nondirectional interaction with trifluoroethanol. Increasing fraction of polyproline II type conformation was detected at low peptide/lipid ratios.

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21

Alte, F., A. Stengel, J. P. Benz, E. Petersen, J. Soll, M. Groll, and B. Bolter. "Ferredoxin:NADPH oxidoreductase is recruited to thylakoids by binding to a polyproline type II helix in a pH-dependent manner." Proceedings of the National Academy of Sciences 107, no. 45 (October 25, 2010): 19260–65. http://dx.doi.org/10.1073/pnas.1009124107.

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22

Ishijima, J., N. Nagasaki, M. Maeshima, and M. Miyano. "RVCaB, a Calcium-binding Protein in Radish Vacuoles, is Predominantly an Unstructured Protein with a Polyproline Type II Helix." Journal of Biochemistry 142, no. 2 (May 23, 2007): 201–11. http://dx.doi.org/10.1093/jb/mvm130.

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23

Scholl, Connor L., Sakae Tsuda, Laurie A. Graham, and Peter L. Davies. "Crystal waters on the nine polyproline type II helical bundle springtail antifreeze protein from Granisotoma rainieri match the ice lattice." FEBS Journal 288, no. 14 (February 3, 2021): 4332–47. http://dx.doi.org/10.1111/febs.15717.

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24

Esipova, N. G., L. E. Ragulina, L. I. Davydova, V. M. Lobachev, V. Yu Makeev, V. G. Bogush, V. G. Tumanyan, and V. G. Debabov. "Left helix of polyproline II type and genesis of β-structures in spidroins 1 and 2 and their recombinant analogs." Biophysics 54, no. 3 (June 2009): 271–74. http://dx.doi.org/10.1134/s0006350909030014.

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25

Reuter, Cédric, Peter Huy, Jörg-Martin Neudörfl, Ronald Kühne, and Hans-Günther Schmalz. "Exercises in Pyrrolidine Chemistry: Gram Scale Synthesis of a Pro-Pro Dipeptide Mimetic with a Polyproline Type II Helix Conformation." Chemistry - A European Journal 17, no. 43 (September 7, 2011): 12037–44. http://dx.doi.org/10.1002/chem.201101704.

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26

Meirson, Tomer, David Bomze, Gal Markel, and Abraham O. Samson. "κ-helix and the helical lock and key model: a pivotal way of looking at polyproline II." Bioinformatics 36, no. 12 (March 14, 2020): 3726–32. http://dx.doi.org/10.1093/bioinformatics/btaa186.

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Abstract Motivation Polyproline II (PPII) is a common conformation, comparable to α-helix and β-sheet. PPII, recently termed with a more generic name—κ-helix, adopts a left-handed structure with 3-fold rotational symmetry. Lately, a new type of binding mechanism—the helical lock and key model was introduced in SH3-domain complexes, where the interaction is characterized by a sliding helical pattern. However, whether this binding mechanism is unique only to SH3 domains is unreported. Results Here, we show that the helical binding pattern is a universal feature of the κ-helix conformation, present within all the major target families—SH3, WW, profilin, MHC-II, EVH1 and GYF domains. Based on a geometric analysis of 255 experimentally solved structures, we found that they are characterized by a distinctive rotational angle along the helical axis. Furthermore, we found that the range of helical pitch varies between different protein domains or peptide orientations and that the interaction is also represented by a rotational displacement mimicking helical motion. The discovery of rotational interactions as a mechanism, reveals a new dimension in the realm of protein–protein interactions, which introduces a new layer of information encoded by the helical conformation. Due to the extensive involvement of the conformation in functional interactions, we anticipate our model to expand the current molecular understanding of the relationship between protein structure and function. Availability and implementation We have implemented the proposed methods in an R package freely available at https://github.com/Grantlab/bio3d. Supplementary information Supplementary data are available at Bioinformatics online.

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27

Bhagwanth, Swapna, Ram K. Mishra, and Rodney L. Johnson. "Development of peptidomimetic ligands of Pro-Leu-Gly-NH2 as allosteric modulators of the dopamine D2 receptor." Beilstein Journal of Organic Chemistry 9 (January 30, 2013): 204–14. http://dx.doi.org/10.3762/bjoc.9.24.

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A variety of stable, small-molecule peptidomimetic ligands have been developed to elucidate the mechanism by which the neuropeptide Pro-Leu-Gly-NH2 (PLG) modulates dopaminergic neurotransmission. Photoaffinity labeling ligands based upon PLG peptidomimetics have been used to establish that PLG binds to the D2 dopamine receptor at a site that is different from the orthosteric site, thus making PLG and its peptidomimetics allosteric modulators of the dopamine receptor. Through the design, synthesis and pharmacological evaluation of conformationally constrained peptidomimetics containing lactam, bicyclic, and spiro-bicyclic scaffolds, support was provided for the hypothesis that the bioactive conformation of PLG is a type II β-turn. In addition, studies with peptidomimetics designed to mimic either a type VI β-turn or polyproline II helix conformation yielded molecules that were able to modulate dopamine receptors because of their ability to place the carboxamide NH2 pharmacophore in the same topological space as that seen in the type II β-turn. Extensive studies with the spiro-bicyclic PLG peptidomimetics also established that both positive and negative modes of modulation were possible for the same series of peptidomimetics simply as a result of minor differences in the stereochemistry about the bridgehead carbon within the scaffold. This information was used to transform existing positive modulators into negative modulators, which demonstrated that small structural changes in the spiro-bicyclic dopamine receptor modulators are capable of causing major changes in the modulatory activity of PLG peptidomimetics.

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28

Raghavan, Bhooma, Kevin J. Skoblenick, Swapna Bhagwanth, Niran Argintaru, Ram K. Mishra, and Rodney L. Johnson. "Allosteric Modulation of the Dopamine D2Receptor by Pro-Leu-Gly-NH2Peptidomimetics Constrained in Either a Polyproline II Helix or a Type II β-Turn Conformation." Journal of Medicinal Chemistry 52, no. 7 (April 9, 2009): 2043–51. http://dx.doi.org/10.1021/jm801575w.

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29

MacDougall, Lindsay K., Mary Elizabeth Gagou, Sally J. Leevers, Ernst Hafen, and Michael D. Waterfield. "Targeted Expression of the Class II Phosphoinositide 3-Kinase in Drosophila melanogaster Reveals Lipid Kinase-Dependent Effects on Patterning and Interactions with Receptor Signaling Pathways." Molecular and Cellular Biology 24, no. 2 (January 15, 2004): 796–808. http://dx.doi.org/10.1128/mcb.24.2.796-808.2004.

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ABSTRACT Phosphoinositide 3-kinases (PI3Ks) can be divided into three distinct classes (I, II, and III) on the basis of their domain structures and the lipid signals that they generate. Functions have been assigned to the class I and class III enzymes but have not been established for the class II PI3Ks. We have obtained the first evidence for a biological function for a class II PI3K by expressing this enzyme during Drosophila melanogaster development and by using deficiencies that remove the endogenous gene. Wild-type and catalytically inactive PI3K_68D transgenes have opposite effects on the number of sensory bristles and on wing venation phenotypes induced by modified epidermal growth factor (EGF) receptor signaling. These results indicate that the endogenous PI3K_68D may act antagonistically to the EGF receptor-stimulated Ras-mitogen-activated protein kinase pathway and downstream of, or parallel to, the Notch receptor. A class II polyproline motif in PI3K_68D can bind the Drk adaptor protein in vitro, primarily via the N-terminal SH3 domain of Drk. Drk may thus be important for the localization of PI3K_68D, allowing it to modify signaling pathways downstream of cell surface receptors. The phenotypes obtained are markedly distinct from those generated by expression of the Drosophila class I PI3K, which affects growth but not pattern formation.

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30

Beausoleil, Eric, and William D. Lubell. "An examination of the steric effects of 5-tert-butylproline on the conformation of polyproline and the cooperative nature of type II to type I helical interconversion." Biopolymers 53, no. 3 (March 2000): 249–56. http://dx.doi.org/10.1002/(sici)1097-0282(200003)53:3<249::aid-bip4>3.0.co;2-j.

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31

Rowińska-Żyrek, Magdalena, Anna Wiȩch, Joanna Wa̧tły, Robert Wieczorek, Danuta Witkowska, Andrzej Ożyhar, and Marek Orłowski. "Copper(II)-Binding Induces a Unique Polyproline Type II Helical Structure within the Ion-Binding Segment in the Intrinsically Disordered F-Domain of Ecdysteroid Receptor from Aedes aegypti." Inorganic Chemistry 58, no. 17 (August 21, 2019): 11782–92. http://dx.doi.org/10.1021/acs.inorgchem.9b01826.

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32

Bhatnagar, Rajendra S., Mark B. Shattuck, Jing Jing Qian, Craig A. Gough, and Steven B. Nicoll. "Theoretical and Experimental Approaches to Identification of a Fiber Surface Cell Binding Domain in Collagen and its Application in Tissue Engineering." Microscopy and Microanalysis 6, S2 (August 2000): 986–87. http://dx.doi.org/10.1017/s1431927600037429.

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Type I collagen comprises between 75-95% of the stationary extracellular matrix of most tissues, forming a continuum in which most of the static cells are anchored. Collagen serves as the track for haptotactic cell migration. The junction between collagen, its receptor integrins, and the cells’ cytoskeleton plays a crucial role in cell differentiation and morphogenesis by serving as the agent for transducing mechanical forces into chemical and biochemical work. The physiological, functional organization of collagen is the solid state in the form of a network of fibers. The only molecules available for engaging the receptors are those located on the fiber surface. Cryogenic scanning force microscopy (SFM) of single molecules of collagen allowed us to correlate surface features with known sequence and stereochemical markers within collagen. Theoretical conformational studies to locate markers for intermolecular recognition and allosteric binding showed that collagen a 1(1) chain residues 766GTPGPQGIAGQRGVV780 generate a distinctive conformation, characterized by a relatively stable (3-bend at the core (Fig. 1) within the triple helical polyproline II conformation extant in the rest of the molecule (1).

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33

Gautam, Gunjan, Syed Arif Abdul Rehman, Preeti Pandey, and Samudrala Gourinath. "Crystal structure of the PEG-bound SH3 domain of myosin IB fromEntamoeba histolyticareveals its mode of ligand recognition." Acta Crystallographica Section D Structural Biology 73, no. 8 (July 28, 2017): 672–82. http://dx.doi.org/10.1107/s2059798317009639.

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The versatility in the recognition of various interacting proteins by the SH3 domain drives a variety of cellular functions. Here, the crystal structure of the C-terminal SH3 domain of myosin IB fromEntamoeba histolytica(EhMySH3) is reported at a resolution of 1.7 Å in native and PEG-bound states. Comparisons with other structures indicated that the PEG molecules occupy protein–protein interaction pockets similar to those occupied by the peptides in other peptide-bound SH3-domain structures. Also, analysis of the PEG-boundEhMySH3 structure led to the recognition of two additional pockets, apart from the conventional polyproline and specificity pockets, that are important for ligand interaction. Molecular-docking studies combined with various comparisons revealed structural similarity betweenEhMySH3 and the SH3 domain of β-Pix, and this similarity led to the prediction thatEhMySH3 preferentially binds targets containing type II-like PXXP motifs. These studies expand the understanding of theEhMySH3 domain and provide extensive structural knowledge, which is expected to help in predicting the interacting partners which function together with myosin IB during phagocytosis inE. histolyticainfections.

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Srinivasan, Mythily, Richard M. Wardrop, Ingrid E. Gienapp, Scott S. Stuckman, Caroline C. Whitacre, and Pravin T. P. Kaumaya. "A Retro-Inverso Peptide Mimic of CD28 Encompassing the MYPPPY Motif Adopts a Polyproline Type II Helix and Inhibits Encephalitogenic T Cells In Vitro." Journal of Immunology 167, no. 1 (July 1, 2001): 578–85. http://dx.doi.org/10.4049/jimmunol.167.1.578.

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Brown, Alaina M., and Neal J. Zondlo. "A Propensity Scale for Type II Polyproline Helices (PPII): Aromatic Amino Acids in Proline-Rich Sequences Strongly Disfavor PPII Due to Proline–Aromatic Interactions." Biochemistry 51, no. 25 (June 14, 2012): 5041–51. http://dx.doi.org/10.1021/bi3002924.

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Ahmed, Shubbir, Anshuman Shukla, and Purnananda Guptasarma. "Folding behavior of a backbone-reversed protein: Reversible polyproline type II to β-sheet thermal transitions in retro-GroES multimers with GroES-like features." Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics 1784, no. 6 (June 2008): 916–23. http://dx.doi.org/10.1016/j.bbapap.2008.02.009.

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Batkhishig, Dashdavaa, Khurelbaatar Bilguun, Purevjav Enkhbayar, Hiroki Miyashita, Robert H. Kretsinger, and Norio Matsushima. "Super Secondary Structure Consisting of a Polyproline II Helix and a β-Turn in Leucine Rich Repeats in Bacterial Type III Secretion System Effectors." Protein Journal 37, no. 3 (April 12, 2018): 223–36. http://dx.doi.org/10.1007/s10930-018-9767-9.

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Kurz, E. M., T. W. Holstein, B. M. Petri, J. Engel, and C. N. David. "Mini-collagens in hydra nematocytes." Journal of Cell Biology 115, no. 4 (November 15, 1991): 1159–69. http://dx.doi.org/10.1083/jcb.115.4.1159.

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We have isolated and characterized four collagen-related c-DNA clones (N-COL 1, N-COL 2, N-COL 3, N-COL 4) that are highly expressed in developing nematocytes in hydra. All four c-DNAs as well as their corresponding transcripts are small in size (600-1,000 bp). The deduced amino acid sequences show that they contain a central region consisting of 14 to 16 Gly-X-Y triplets. This region is flanked amino-terminal by a stretch of 14-23 proline residues and carboxy-terminal by a stretch of 6-9 prolines. At the NH2- and COOH-termini are repeated patterns of cysteine residues that are highly conserved between the molecules. A model is proposed which consists of a central stable collagen triple helix of 12-14 nm length from which three 9-22 nm long polyproline II type helices emerge at both ends. Disulfide linkage between cysteine-rich segments in these helices could lead to the formation of oligomeric network structures. Electrophoretic characterization of nematocyst extracts allows resolution of small proline-rich polypeptides that correspond in size to the cloned sequences.

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Top, Deniz, Jolene A. Read, Sandra J. Dawe, Raymond T. Syvitski, and Roy Duncan. "Cell-Cell Membrane Fusion Induced by p15 Fusion-associated Small Transmembrane (FAST) Protein Requires a Novel Fusion Peptide Motif Containing a Myristoylated Polyproline Type II Helix." Journal of Biological Chemistry 287, no. 5 (December 14, 2011): 3403–14. http://dx.doi.org/10.1074/jbc.m111.305268.

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Caporale, Andrea, Simone Adorinni, Doriano Lamba, and Michele Saviano. "Peptide–Protein Interactions: From Drug Design to Supramolecular Biomaterials." Molecules 26, no. 5 (February 25, 2021): 1219. http://dx.doi.org/10.3390/molecules26051219.

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The self-recognition and self-assembly of biomolecules are spontaneous processes that occur in Nature and allow the formation of ordered structures, at the nanoscale or even at the macroscale, under thermodynamic and kinetic equilibrium as a consequence of specific and local interactions. In particular, peptides and peptidomimetics play an elected role, as they may allow a rational approach to elucidate biological mechanisms to develop new drugs, biomaterials, catalysts, or semiconductors. The forces that rule self-recognition and self-assembly processes are weak interactions, such as hydrogen bonding, electrostatic attractions, and van der Waals forces, and they underlie the formation of the secondary structure (e.g., α-helix, β-sheet, polyproline II helix), which plays a key role in all biological processes. Here, we present recent and significant examples whereby design was successfully applied to attain the desired structural motifs toward function. These studies are important to understand the main interactions ruling the biological processes and the onset of many pathologies. The types of secondary structure adopted by peptides during self-assembly have a fundamental importance not only on the type of nano- or macro-structure formed but also on the properties of biomaterials, such as the types of interaction, encapsulation, non-covalent interaction, or covalent interaction, which are ultimately useful for applications in drug delivery.

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Stoddart, Cheryl A., Romas Geleziunas, Sharon Ferrell, Valerie Linquist-Stepps, Mary E. Moreno, Christopher Bare, Weiduan Xu, et al. "Human Immunodeficiency Virus Type 1 Nef-Mediated Downregulation of CD4 Correlates with Nef Enhancement of Viral Pathogenesis." Journal of Virology 77, no. 3 (February 1, 2003): 2124–33. http://dx.doi.org/10.1128/jvi.77.3.2124-2133.2003.

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ABSTRACT The nef gene products encoded by human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus type 1 (SIV-1) increase viral loads in infected hosts and accelerate clinical progression to AIDS. Nef exhibits a spectrum of biological activities, including the ability to downregulate surface expression of CD4 and major histocompatibility complex (MHC) class I antigens, to alter the state of T-cell activation, and to enhance the infectivity of viral particles. To determine which of these in vitro functions most closely correlates with the pathogenic effects of Nef in vivo, we constructed recombinant HIV-1 NL4-3 viruses carrying mutations within the nef gene that selectively impair these functions. These mutant viruses were evaluated for pathogenic potential in severe combined immunodeficiency (SCID) mice implanted with human fetal thymus and liver (SCID-hu Thy/Liv mice), in which virus-mediated depletion of thymocytes is known to be Nef dependent. Disruption of the polyproline type II helix (Pxx)4 within Nef (required for binding of Hck and p21-activated kinase-like kinases, downregulation of MHC class I, and enhancement of HIV-1 infectivity in vitro but dispensable for CD4 downregulation) did not impair thymocyte depletion in virus-infected Thy/Liv human thymus implants. Conversely, three separate point mutations in Nef that compromised its ability to downregulate CD4 attenuated thymocyte depletion while not diminishing viral replication. These findings indicate that the functional ability of Nef to downregulate CD4 and not MHC class I downregulation, Hck or PAK binding, or (Pxx)4-associated enhancement of infectivity most closely correlates with Nef-mediated enhancement of HIV-1 pathogenicity in vivo. Nef-mediated CD4 downregulation merits consideration as a new target for the development of small-molecule inhibitors.

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Adolph, Dörte, Nadine Flach, Katharina Mueller, Dirk H. Ostareck, and Antje Ostareck-Lederer. "Deciphering the Cross Talk between hnRNP K and c-Src: the c-Src Activation Domain in hnRNP K Is Distinct from a Second Interaction Site." Molecular and Cellular Biology 27, no. 5 (December 18, 2006): 1758–70. http://dx.doi.org/10.1128/mcb.02014-06.

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ABSTRACT The protein tyrosine kinase c-Src is regulated by two intramolecular interactions. The repressed state is achieved through the interaction of the Src homology 2 (SH2) domain with the phosphorylated C-terminal tail and the association of the SH3 domain with a polyproline type II helix formed by the linker region between SH2 and the kinase domain. hnRNP K, the founding member of the KH domain protein family, is involved in chromatin remodeling, regulation of transcription, and translation of specific mRNAs and is a target in different signal transduction pathways. In particular, it functions as a specific activator and a substrate of the tyrosine kinase c-Src. Here we address the question how hnRNP K interacts with and activates c-Src. We define the proline residues in hnRNP K in the proline-rich motifs P2 (amino acids [aa] 285 to 297) and P3 (aa 303 to 318), which are necessary and sufficient for the specific activation of c-Src, and we dissect the amino acid sequence (aa 216 to 226) of hnRNP K that mediates a second interaction with c-Src. Our findings indicate that the interaction with c-Src and the activation of the kinase are separable functions of hnRNP K. hnRNP K acts as a scaffold protein that integrates signaling cascades by facilitating the cross talk between kinases and factors that mediate nucleic acid-directed processes.

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Nobuhisa, Ikuo, Ryu Takeya, Kenji Ogura, Noriko Ueno, Daisuke Kohda, Fuyuhiko Inagaki, and Hideki Sumimoto. "Activation of the superoxide-producing phagocyte NADPH oxidase requires co-operation between the tandem SH3 domains of p47phox in recognition of a polyproline type II helix and an adjacent α-helix of p22phox." Biochemical Journal 396, no. 1 (April 26, 2006): 183–92. http://dx.doi.org/10.1042/bj20051899.

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Activation of the superoxide-producing phagocyte NADPH oxidase, crucial for host defence, requires an SH3 (Src homology 3)-domain-mediated interaction of the regulatory protein p47phox with p22phox, a subunit of the oxidase catalytic core flavocytochrome b558. Although previous analysis of a crystal structure has demonstrated that the tandem SH3 domains of p47phox sandwich a short PRR (proline-rich region) of p22phox (amino acids 151–160), containing a polyproline II helix, it has remained unknown whether this model is indeed functional in activation of the oxidase. In the present paper we show that the co-operativity between the two SH3 domains of p47phox, as expected from the model, is required for oxidase activation. Deletion of the linker between the p47phox SH3 domains results not only in a defective binding to p22phox but also in a loss of the activity to support superoxide production. The present analysis using alanine-scanning mutagenesis identifies Pro152, Pro156 and Arg158 in the p22phox PRR as residues indispensable for the interaction with p47phox. Pro152 and Pro156 are recognized by the N-terminal SH3 domain, whereas Arg158 contacts with the C-terminal SH3 domain. Amino acid substitution for any of the three residues in the p22phox PRR abrogates the superoxide-producing activity of the oxidase reconstituted in intact cells. The bis-SH3-mediated interaction of p47phox with p22phox thus functions to activate the phagocyte oxidase. Furthermore, we provide evidence that a region C-terminal to the PRR of p22phox (amino acids 161–164), adopting an α-helical conformation, participates in full activation of the phagocyte oxidase by fortifying the association with the p47phox SH3 domains.

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Mucha, Piotr, Emilia Sikorska, Piotr Rekowski, and Jarosław Ruczyński. "Interaction of Arginine-Rich Cell-Penetrating Peptides with an Artificial Neuronal Membrane." Cells 11, no. 10 (May 13, 2022): 1638. http://dx.doi.org/10.3390/cells11101638.

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Arginine-rich cell-penetrating peptides (RRCPPs) exhibit intrinsic neuroprotective effects on neurons injured by acute ischemic stroke. Conformational properties, interaction, and the ability to penetrate the neural membrane are critical for the neuroprotective effects of RRCCPs. In this study, we applied circular dichroism (CD) spectroscopy and coarse-grained molecular dynamics (CG MD) simulations to investigate the interactions of two RRCPPs, Tat(49–57)-NH2 (arginine-rich motif of Tat HIV-1 protein) and PTD4 (a less basic Ala-scan analog of the Tat peptide), with an artificial neuronal membrane (ANM). CD spectra showed that in an aqueous environment, such as phosphate-buffered saline, the peptides mostly adopted a random coil (PTD4) or a polyproline type II helical (Tat(49–57)-NH2) conformation. On the other hand, in the hydrophobic environment of the ANM liposomes, the peptides showed moderate conformational changes, especially around 200 nm, as indicated by CD curves. The changes induced by the liposomes were slightly more significant in the PTD4 peptide. However, the nature of the conformational changes could not be clearly defined. CG MD simulations showed that the peptides are quickly attracted to the neuronal lipid bilayer and bind preferentially to monosialotetrahexosylganglioside (DPG1) molecules. However, the peptides did not penetrate the membrane even at increasing concentrations. This suggests that the energy barrier required to break the strong peptide–lipid electrostatic interactions was not exceeded in the simulated models. The obtained results show a correlation between the potential of mean force parameter and a peptide’s cell membrane-penetrating ability and neuroprotective properties.

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Tahoun, Amin, Gabriella Siszler, Kevin Spears, Sean McAteer, Jai Tree, Edith Paxton, Trudi L. Gillespie, et al. "Comparative Analysis of EspF Variants in Inhibition of Escherichia coli Phagocytosis by Macrophages and Inhibition of E. coli Translocation through Human- and Bovine-Derived M Cells." Infection and Immunity 79, no. 11 (August 29, 2011): 4716–29. http://dx.doi.org/10.1128/iai.00023-11.

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ABSTRACTThe EspF protein is secreted by the type III secretion system of enteropathogenic and enterohemorrhagicEscherichia coli(EPEC and EHEC, respectively). EspF sequences differ between EHEC O157:H7, EHEC O26:H11, and EPEC O127:H6 in terms of the number of SH3-binding polyproline-rich repeats and specific residues in these regions, as well as residues in the amino domain involved in cellular localization. EspFO127is important for the inhibition of phagocytosis by EPEC and also limits EPEC translocation through antigen-sampling cells (M cells). EspFO127has been shown to have effects on cellular organelle function and interacts with several host proteins, including N-WASP and sorting nexin 9 (SNX9). In this study, we compared the capacities of differentespFalleles to inhibit (i) bacterial phagocytosis by macrophages, (ii) translocation through an M-cell coculture system, and (iii) uptake by and translocation through cultured bovine epithelial cells. TheespFgene fromE. coliserotype O157 (espFO157) allele was significantly less effective at inhibiting phagocytosis and also had reduced capacity to inhibitE. colitranslocation through a human-derivedin vitroM-cell coculture system in comparison toespFO127andespFO26. In contrast,espFO157was the most effective allele at restricting bacterial uptake into and translocation through primary epithelial cells cultured from the bovine terminal rectum, the predominant colonization site of EHEC O157 in cattle and a site containing M-like cells. Although LUMIER binding assays demonstrated differences in the interactions of the EspF variants with SNX9 and N-WASP, we propose that other, as-yet-uncharacterized interactions contribute to the host-based variation in EspF activity demonstrated here.

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Lewitzky, Marc, Maria Harkiolaki, Marie-Charlotte Domart, E. Yvonne Jones, and Stephan M. Feller. "Mona/Gads SH3C Binding to Hematopoietic Progenitor Kinase 1 (HPK1) Combines an Atypical SH3 Binding Motif, R/KXXK, with a Classical PXXP Motif Embedded in a Polyproline Type II (PPII) Helix." Journal of Biological Chemistry 279, no. 27 (April 20, 2004): 28724–32. http://dx.doi.org/10.1074/jbc.m402745200.

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Lokes, K. P., D. S. Avetikov, S. O. Stavitsky, O. O. Rozkolupa, and N. S. Lutsenko. "THE FEATURES OF THE FACE SKIN CONSTRUCTION THAT INFLUENCE ON THE FORMATION OF CICATRICAL TISSUES DURING SUGICAL INTERVENTIONS." Ukrainian Dental Almanac, no. 4 (December 26, 2019): 19–23. http://dx.doi.org/10.31718/2409-0255.4.2019.03.

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Formation of pathological scars of maxillofacial localization after surgery is a significant and widespread problem of modern surgical stomatology and maxillofacial surgery. A significant percentage of patients who needs planned and urgent surgical interventions cause rapid development of reconstructive-restorative surgery of the maxillofacial region. The analysis of domestic and foreign literary sources was devoted to the peculiarities of the structure of the skin of the head and neck and the optimization of the skin incisions of this localization. Functional features of human skin depend on the mechanical properties of the dermis, which provides elasticity and resistance to stretching. Changes in the biomechanics of the dermis occur during aging, excessive insolation, scarring, and fibrosis. In addition, mechanical changes in the extracellular matrix of the skin affect the activity and phenotype of the fibroblasts, which adapt the stiffness of the cytoskeleton. Extracellular matrix stiffness defines and maintains cell identity and influences the proliferation, differentiation, migration and expression of skin cells. The extracellular matrix has been regarded for a long time as a structure with simple architectonics. But, due to modern research, it is known that this complex formation is highly specialized. The different classes of macromolecules that make up the extracellular matrix determine its biological functions. For example, collagen proteins are responsible for the tensile strength of tissues, proteoglycans and glycosaminoglycan are important for hydration and compression resistance, and glycoproteins such as laminas facilitate cell attachment. The largest structures of the extracellular matrix are elastin fibers, which are mainly localized in tissues subject to high mechanical stress, such as skin, lungs, or arteries. These structures represent a very complex organization whose core consists of elastin surrounded by a mantle of microfibrils. Collagen proteins in the dermis contain mainly type I collagen (85% - 90%) with smaller amounts of type III collagen (10% - 15%). Skin fibroblasts synthesize individual collagen type I and III polypeptide chains as precursor molecules, called procollagens. During the formation of insoluble collagen fibrils, specific proteases break down the carboxy- and amino-terminal domains, forming pN-collagen (procollagen from which the carboxy-terminal domain propeptide is cleaved) and pC-collagen (procollagen, from which the amino-terminal propeptide is cleaved). Because type I and III procollagen, pN-collagen and pC-collagen are precursors of mature collagen molecules, their level usually reflects the level of collagen biosynthesis. Collagens and elastin contain highly abundant fibrils, each of which is repeated in a sequence enriched in the conformation of polyproline II, cross-linked, insoluble in assembly and resistant to the most photolytic enzymes. The monomeric block of type I collagen consists of two extended chains α1 and one chain α2, twisted together into a triple helix. The direction of collagen and elastin fibers, according to biomechanical studies, has a significant effect on the enlargement of the wound on the head skin and the tension when closing its edges. The overwhelming reduction of tension and accordingly the improvement of reparative processes in the skin occur when the incision lines correspond to the so-called "golden spiral". Conclusion. Thus, the analysis of domestic and foreign literature sources indicates the relevance of the selected topics, the need for further studies on the biomechanical and histological substantiation of incisions, which are due to the peculiarities of the structure of the skin in the head and neck to create optimal conditions for reparative regeneration.

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Panjarian, Shoghag, Shugui Chen, John Engen, and Thomas Smithgall. "Enhanced SH3:Linker Interaction Suppresses Activating Mutations of the c-Abl Protein-Tyrosine Kinase." Blood 116, no. 21 (November 19, 2010): 1208. http://dx.doi.org/10.1182/blood.v116.21.1208.1208.

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Abstract Abstract 1208 Bcr-Abl, the chimeric protein-tyrosine kinase expressed as a result of the Philadelphia chromosome translocation, plays a pivotal role in the initiation and maintenance of chronic myelogenous leukemia (CML). Imatinib (Gleevec) is an ATP-competitive Bcr-Abl inhibitor that selectively kills Bcr-Abl+ CML cells. Despite its clinical success, imatinib is less effective in the advanced stages of CML due to the emergence of drug resistance caused by point mutations in the Abl kinase domain. Second generation Bcr-Abl inhibitors such as dasatinib and nilotinib are active against most imatinib-resistant forms of Bcr-Abl, with the exception of the T315I “gatekeeper” mutant. The Abl gatekeeper residue (Thr315) is located between the ATP-binding site and an adjacent hydrophobic pocket, and forms a key hydrogen bond with imatinib. Additionally, the T315I mutation produces a strong activating effect on the downregulated c-Abl “core,” consisting of the myristoylated N-terminal Ncap, tandem SH3 and SH2 regulatory domains, the SH2-kinase linker, which forms a polyproline type II helix for internal SH3 docking, and the tyrosine kinase domain. Using hydrogen-exchange mass spectrometry, we recently found that the T315I mutation not only induced conformational changes in the Abl kinase domain as expected, but also at a distance in the RT-loop of the SH3 domain. Such changes may allosterically contribute to kinase domain activation by disturbing the negative regulatory influence of SH3:linker interaction. Recently, a new class of allosteric Bcr-Abl inhibitors has been reported that targets the myristate-binding pocket of Abl, which localizes to C-lobe of the kinase domain and away from the active site. Together with our finding that the T315I mutation perturbs SH3:linker interaction, these inhibitors support the existence of an extensive network of allosteric interactions that work together to regulate Abl kinase activity. In this project, we investigated whether enhanced SH3:linker interaction can allosterically reverse the activating effects of the T315I imatinib resistance mutation as well as mutations of the N-terminal myristoylation site and myristic acid binding pocket. We created modified versions of Abl [High Affinity Linker proteins (HALs)] by mutating multiple residues within the SH2-kinase linker to proline, thereby enhancing the SH3 domain binding affinity. Using mammalian cell-based expression assays and immunoblotting with phosphospecific antibodies, we identified five of eleven Abl-HAL proteins that did not exhibit changes in basal kinase activity. The Abl-HAL protein with the greatest enhancement of SH3:linker interaction was then combined with the T315I mutation, a myristoylation-defective mutant, and a myristic acid binding pocket mutation. Remarkably, this HAL substitution completely reversed the activating effect of the myristic acid binding pocket mutation, while substantially suppressing the activity of Abl T315I and the myristoylation-defective mutant. These results indicate that stabilization of SH3:linker interaction allosterically represses Abl activation by a wide variety of mechanisms, and suggests a new approach to allosteric control of Bcr-Abl kinase activity. Disclosures: No relevant conflicts of interest to declare.

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Cayrou, Chloé, Astrid Walrant, Delphine Ravault, Karine Guitot, Sylvie Noinville, Sandrine Sagan, Thierry Brigaud, Simon Gonzalez, Sandrine Ongeri, and Grégory Chaume. "Incorporation of CF₃-pseudoprolines into polyproline type II foldamers confers promising biophysical features." Chemical Communications, 2024. http://dx.doi.org/10.1039/d4cc02895c.

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The development and the use of fluorinated polyproline-type II (PPII) foldamers are still underexplored. Herein, trifluoromethyl pseudoprolines have been incorporated into polyproline backbones without affecting their PPII helicity. The ability...

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Rojas, Roberto, Mónica Aróstica, Patricio Carvajal-Rondanelli, Fernando Albericio, Fanny Guzmán, and Constanza Cárdenas. "Relationship between type II polyproline helix secondary structure and thermal hysteresis activity of short homopeptides." Electronic Journal of Biotechnology, August 2022. http://dx.doi.org/10.1016/j.ejbt.2022.08.003.

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