Journal articles: 'Synthese interactive'

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Weber, Ute, Laszlo Zsolnai, and Gottfried Hüttner. "Synthesen und Strukturen von Distibankomplexen / Syntheses and Structures of Distibane Complexes." Zeitschrift für Naturforschung B 40, no. 11 (November 1, 1985): 1430–36. http://dx.doi.org/10.1515/znb-1985-1103.

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Stibanes RSbHal2 are reductivly coupled by interaction with Na2M2(CO)10 (M = Cr, W) or Cp(CO)2MnTHF. The resulting distibanes RS̲b̲(Hal)-(Hal)S̲b̲R are coordinated to sixteen electron LnM-fragments (LnM=M(CO)5, Cp(CO)2Mn). Both the meso and d/l stereoisomeres are structurally characterised by X-ray analyses.

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Spikes, Tobias E., Martin G. Montgomery, and John E. Walker. "Interface mobility between monomers in dimeric bovine ATP synthase participates in the ultrastructure of inner mitochondrial membranes." Proceedings of the National Academy of Sciences 118, no. 8 (February 4, 2021): e2021012118. http://dx.doi.org/10.1073/pnas.2021012118.

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The ATP synthase complexes in mitochondria make the ATP required to sustain life by a rotary mechanism. Their membrane domains are embedded in the inner membranes of the organelle, and they dimerize via interactions between their membrane domains. The dimers form extensive chains along the tips of the cristae with the two rows of monomeric catalytic domains extending into the mitochondrial matrix at an angle to each other. Disruption of the interface between dimers by mutation affects the morphology of the cristae severely. By analysis of particles of purified dimeric bovine ATP synthase by cryo-electron microscopy, we have shown that the angle between the central rotatory axes of the monomeric complexes varies between ca. 76 and 95°. These particles represent active dimeric ATP synthase. Some angular variations arise directly from the catalytic mechanism of the enzyme, and others are independent of catalysis. The monomer–monomer interaction is mediated mainly by j subunits attached to the surface of wedge-shaped protein-lipid structures in the membrane domain of the complex, and the angular variation arises from rotational and translational changes in this interaction, and combinations of both. The structures also suggest how the dimeric ATP synthases might be interacting with each other to form the characteristic rows along the tips of the cristae via other interwedge contacts, molding themselves to the range of oligomeric arrangements observed by tomography of mitochondrial membranes, and at the same time allowing the ATP synthase to operate under the range of physiological conditions that influence the structure of the cristae.

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Li, Chunhong, Sreelatha Sarangapani, Qian Wang, Kumar Nadimuthu, and Rajani Sarojam. "Metabolic Engineering of the Native Monoterpene Pathway in Spearmint for Production of Heterologous Monoterpenes Reveals Complex Metabolism and Pathway Interactions." International Journal of Molecular Sciences 21, no. 17 (August 26, 2020): 6164. http://dx.doi.org/10.3390/ijms21176164.

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Spearmint produces and stores large amounts of monoterpenes, mainly limonene and carvone, in glandular trichomes and is the major natural source of these compounds. Towards producing heterologous monoterpenes in spearmint, we first reduced the flux into the native limonene pathway by knocking down the expression of limonene synthase (MsLS) by RNAi method. The MsLS RNAi lines exhibited a huge reduction in the synthesis of limonene and carvone. Detailed GC-MS and LC-MS analysis revealed that MsLS RNAi plants also showed an increase in sesquiterpene, phytosterols, fatty acids, flavonoids, and phenolic metabolites, suggesting an interaction between the MEP, MVA shikimate and fatty acid pathways in spearmint. Three different heterologous monoterpene synthases namely, linalool synthase and myrcene synthase from Picea abies and geraniol synthase from Cananga odorata were cloned and introduced independently into the MsLS RNAi mutant background. The expression of these heterologous terpene synthases resulted mainly in production of monoterpene derivatives. Of all the introduced monoterpenes geraniol showed the maximum number of derivatives. Our results provide new insights into MEP pathway interactions and regulation and reveals the existence of mechanisms for complex metabolism of monoterpenes in spearmint.

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Moolhuijzen, Paula M., Mariano Jordi Muria-Gonzalez, Robert Syme, Catherine Rawlinson, Pao Theen See, Caroline S. Moffat, and Simon R. Ellwood. "Expansion and Conservation of Biosynthetic Gene Clusters in Pathogenic Pyrenophora spp." Toxins 12, no. 4 (April 9, 2020): 242. http://dx.doi.org/10.3390/toxins12040242.

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Pyrenophora is a fungal genus responsible for a number of major cereal diseases. Although fungi produce many specialised or secondary metabolites for defence and interacting with the surrounding environment, the repertoire of specialised metabolites (SM) within Pyrenophora pathogenic species remains mostly uncharted. In this study, an in-depth comparative analysis of the P. teres f. teres, P teres f. maculata and P. tritici-repentis potential to produce SMs, based on in silico predicted biosynthetic gene clusters (BGCs), was conducted using genome assemblies from PacBio DNA reads. Conservation of BGCs between the Pyrenophora species included type I polyketide synthases, terpene synthases and the first reporting of a type III polyketide synthase in P teres f. maculata. P. teres isolates exhibited substantial expansion of non-ribosomal peptide synthases relative to P. tritici-repentis, hallmarked by the presence of tailoring cis-acting nitrogen methyltransferase domains. P. teres isolates also possessed unique non-ribosomal peptide synthase (NRPS)-indole and indole BGCs, while a P. tritici-repentis phytotoxin BGC for triticone production was absent in P. teres. These differences highlight diversification between the pathogens that reflects their different evolutionary histories, host adaption and lifestyles.

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Webby, Celia J., Mark L. Patchett, and Emily J. Parker. "Characterization of a recombinant type II 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Helicobacter pylori." Biochemical Journal 390, no. 1 (August 9, 2005): 223–30. http://dx.doi.org/10.1042/bj20050259.

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DAH7P (3-Deoxy-D-arabino-heptulosonate 7-phosphate) synthase catalyses the condensation reaction between phosphoenolpyruvate (PEP) and D-erythrose 4-phosphate (E4P) as the first committed step in the biosynthesis of aromatic compounds in plants and micro-organisms. Previous work has identified two families of DAH7P synthases based on sequence similarity and molecular mass, with the majority of the mechanistic and structural studies being carried out on the type I paralogues from Escherichia coli. Whereas a number of organisms possess genes encoding both type I and type II DAH7P synthases, the pathogen Helicobacter pylori has only a single, type II, enzyme. Recombinant DAH7P synthase from H. pylori was partially solubilized by co-expression with chaperonins GroEL/GroES in E. coli, and purified to homogeneity. The enzyme reaction follows an ordered sequential mechanism with the following kinetic parameters: Km (PEP), 3 μM; Km (E4P), 6 μM; and kcat, 3.3 s−1. The enzyme reaction involves interaction of the si face of PEP with the re face of E4P. H. pylori DAH7P synthase is not inhibited by phenylalanine, tyrosine, tryptophan or chorismate. EDTA inactivates the enzyme, and activity is restored by a range of bivalent metal ions, including (in order of decreasing effectiveness) Co2+, Mn2+, Ca2+, Mg2+, Cu2+ and Zn2+. Analysis of type II DAH7P synthase sequences reveals several highly conserved motifs, and comparison with the type I enzymes suggests that catalysis by these two enzyme types occurs on a similar active-site scaffold and that the two DAH7P synthase families may indeed be distantly related.

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Biuković, Goran, Sandip Basak, Malathy Sony Subramanian Manimekalai, Sankaranarayanan Rishikesan, Manfred Roessle, Thomas Dick, Srinivasa P. S. Rao, Cornelia Hunke, and Gerhard Grüber. "Variations of Subunit ε of the Mycobacterium tuberculosis F1FoATP Synthase and a Novel Model for Mechanism of Action of the Tuberculosis Drug TMC207." Antimicrobial Agents and Chemotherapy 57, no. 1 (October 22, 2012): 168–76. http://dx.doi.org/10.1128/aac.01039-12.

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ABSTRACTThe subunit ε of bacterial F1FOATP synthases plays an important regulatory role in coupling and catalysis via conformational transitions of its C-terminal domain. Here we present the first low-resolution solution structure of ε ofMycobacterium tuberculosis(Mtε) F1FOATP synthase and the nuclear magnetic resonance (NMR) structure of its C-terminal segment (Mtε103–120).Mtε is significantly shorter (61.6 Å) than forms of the subunit in other bacteria, reflecting a shorter C-terminal sequence, proposed to be important in coupling processes via the catalytic β subunit. The C-terminal segment displays an α-helical structure and a highly positive surface charge due to the presence of arginine residues. Using NMR spectroscopy, fluorescence spectroscopy, and mutagenesis, we demonstrate that the new tuberculosis (TB) drug candidate TMC207, proposed to bind to the proton translocatingc-ring, also binds toMtε. A model for the interaction of TMC207 with both ε and thec-ring is presented, suggesting that TMC207 forms a wedge between the two rotating subunits by interacting with the residues W15 and F50 of ε and thec-ring, respectively. T19 and R37 of ε provide the necessary polar interactions with the drug molecule. This new model of the mechanism of TMC207 provides the basis for the design of new drugs targeting the F1FOATP synthase inM. tuberculosis.

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Mühleip, Alexander W., Friederike Joos, Christoph Wigge, Achilleas S. Frangakis, Werner Kühlbrandt, and Karen M. Davies. "Helical arrays of U-shaped ATP synthase dimers form tubular cristae in ciliate mitochondria." Proceedings of the National Academy of Sciences 113, no. 30 (July 11, 2016): 8442–47. http://dx.doi.org/10.1073/pnas.1525430113.

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F1Fo-ATP synthases are universal energy-converting membrane protein complexes that synthesize ATP from ADP and inorganic phosphate. In mitochondria of yeast and mammals, the ATP synthase forms V-shaped dimers, which assemble into rows along the highly curved ridges of lamellar cristae. Using electron cryotomography and subtomogram averaging, we have determined the in situ structure and organization of the mitochondrial ATP synthase dimer of the ciliate Paramecium tetraurelia. The ATP synthase forms U-shaped dimers with parallel monomers. Each complex has a prominent intracrista domain, which links the c-ring of one monomer to the peripheral stalk of the other. Close interaction of intracrista domains in adjacent dimers results in the formation of helical ATP synthase dimer arrays, which differ from the loose dimer rows in all other organisms observed so far. The parameters of the helical arrays match those of the cristae tubes, suggesting the unique features of the P. tetraurelia ATP synthase are directly responsible for generating the helical tubular cristae. We conclude that despite major structural differences between ATP synthase dimers of ciliates and other eukaryotes, the formation of ATP synthase dimer rows is a universal feature of mitochondria and a fundamental determinant of cristae morphology.

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Gu, Ying, and Chris Somerville. "Cellulose synthase interacting protein." Plant Signaling & Behavior 5, no. 12 (December 2010): 1571–74. http://dx.doi.org/10.4161/psb.5.12.13621.

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Sotodosos-Alonso, Laura, María García-García, Enrique Calvo, Aleksandra Norczyk-Simón, Jesús Vázquez, Asier Echarri, and Miguel A. Del Pozo. "Cell tension controlling pathways and nutrient availability regulate plasma membrane ATP synthase trafficking." IBJ Plus 1, s5 (June 3, 2022): 45. http://dx.doi.org/10.24217/2531-0151.22v1s5.00045.

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Introduction: The interplay between mechanical stress and cell metabolism is an emerging topic. However, the mechanotransduction pathways coordinating cell metabolism to the tensional status of the cell are poorly understood. Here, we provide several evidences suggesting that caveolae – mechanosensitive plasma membrane invaginations-, nutrient availability and cell tension controlling conditions are important for the biology of mitochondrial ATP synthase. Material and Methods: For achieving the caveolar interactome, plasma membrane biotinylation and co-localization experiments, we have used human retinal pigment epithelial-1 (RPE-1) cells, murine vascular aortic smooth muscle (MOVAS) cells and mouse embryonic fibroblasts (MEF). We used proximity-dependent biotin identification (BioID) and mass spectrometry to obtain the different interactomes of caveolar components. For plasma membrane (PM) localization of the ATP synthase we used PM biotinylation under different metabolic and mechanical conditions (nutrient starving, cell confluence). To study co-localization, we performed Proximity Ligation Assays (PLAs) in combination with mitochondrial and caveolar markers. Results: First, we have identified the interactome of all core caveolar components. Among the interactors, we identified subunits α and β of the mitochondrial ATP synthase, which interact with most of the caveolar components. Apart from its main localization at the inner mitochondrial membrane, the ATP synthase has also been detected in the PM, facing the extracellular space; this pool is known as ecto-ATP synthase. We show that the interaction with Caveolin-1 (Cav1), one of the main components of caveolae, occurs outside caveolae and mitochondria. In addition, the presence of ecto- ATP synthase at the PM is dependent on Cav1. Furthermore, conditions regulating cell tension, and metabolic challenges that promote autophagy, impinge on ecto-ATP synthase trafficking Conclusions: This study has characterized the interactome of caveolar components and has focused on the subunits α and β of the ATP synthase, which are also present at the PM. These subunits interact with Cav-1, but this interaction seems to occur in intracellular trafficking vesicles. Moreover, this process could be altered by mechanical cues and nutrient deprivation. Thus, our study suggests that trafficking routes regulating PM residents, and regulated by several caveolar components, are linked to nutrient starvation and mitochondrial biology.

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Rode, W., and A. Leś. "Molecular mechanism of thymidylate synthase-catalyzed reaction and interaction of the enzyme with 2- and/or 4-substituted analogues of dUMP and 5-fluoro-dUMP." Acta Biochimica Polonica 43, no. 1 (March 31, 1996): 133–42. http://dx.doi.org/10.18388/abp.1996_4524.

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Thymidylate synthase is a target enzyme in anticancer, antiviral, antifungal and antiprotozoan chemotherapy. With two dUMP analogues, 5-fluoro-dUMP (FdUMP) and 5-(trifluoromethyl)-dUMP (CF3dUMP), strong thymidylate synthase inhibitors and active forms of drugs, the inhibition mechanism is based on the reaction mechanism. Recent comparative studies of new dUMP analogues, containing more than one substituent in the pyrimidine ring, showed that substitution of the pyrimidine ring C(4) = O group in FdUMP by either C(4) = N-OH group (in N4-hydroxy-FdCMP) or C(4) = S group (in 4-thio-FdUMP) preserves high inhibitory potency of the drug but may alter its specificity for thymidylate synthases from various sources, which differ in sensitivity to slow-binding inhibition by FdUMP. Informations suggesting mechanisms responsible for the foregoing have been reviewed, including results of molecular modeling studies suggesting interaction of the pyrimidine C(4) = O group, or its modification, with the N5,10-methylene.(ABSTRACT TRUNCATED)

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Volk, Kathrin, Sven D. Breunig, Raphaela Rid, Julia Herzog, Maria Bräuer, Harald Hundsberger, Christian Klein, Norbert Müller, and Kamil Önder. "Structural analysis and interaction studies of acyl-carrier protein (acpP) of Staphylococcus aureus, an extraordinarily thermally stable protein." Biological Chemistry 398, no. 1 (January 1, 2017): 125–33. http://dx.doi.org/10.1515/hsz-2016-0185.

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Abstract Acyl-carrier-protein (acpP) is an essential protein in fatty acid biosynthesis of Staphylococcus aureus [Cronan, J.E. and Thomas, J. (2009). Complex enzymes in microbial natural product biosynthesis, part B: polyketides, aminocoumarins and carbohydrates. Method. Enzymol. 459, 395–433; Halavaty, A.S., Kim, Y., Minasov, G., Shuvalova, L., Dubrovska, I., Winsor, J., Zhou, M., Onopriyenko, O., Skarina, T., Papazisi, L., et al. (2012). Structural characterization and comparison of three acyl-carrier-protein synthases from pathogenic bacteria. Acta Crystallogr. Sect. D Biol. Crystallogr. 68, 1359–1370]. The inactive apo-form is converted to the active holo-enzyme by acyl-carrier protein synthase (acpS) through addition of a 4′-phosphopantetheine group from coenzyme A to a conserved serine residue of acpP [Flugel, R.S., Hwangbo, Y., Lambalot, R.H., Cronan, J.E., and Walsh, C.T. (2000). Holo-(acyl-carrier protein) synthase and phosphopantetheinyl transfer in Escherichia coli. J. Biol. Chem. 275, 959–968; Lambalot, R.H. and Walsh, C.T. (1995). Cloning, overproduction, and characterization of the Escherichia coli holo-acyl-carrier protein synthase. J. Biol. Chem. 270, 24658–24661]. Once activated, acpP acts as an anchor for the growing fatty acid chain. Structural data from X-ray crystallographic analysis reveals that, despite its small size (8 kDa), acpP adopts a distinct, mostly α-helical structure when complexed with acpS [Halavaty, A.S., Kim, Y., Minasov, G., Shuvalova, L., Dubrovska, I., Winsor, J., Zhou, M., Onopriyenko, O., Skarina, T., Papazisi, L., et al. (2012). Structural characterization and comparison of three acyl-carrier-protein synthases from pathogenic bacteria. Acta Crystallogr. Sect. D Biol. Crystallogr. 68, 1359–1370; Byers, D.M. and Gong, H. (2007). Acyl carrier protein: structure–function relationships in a conserved multifunctional protein family. Biochem. Cell Biol. 85, 649–662]. We expressed and purified recombinant, active S. aureus acpP from Escherichia coli and mimicked the beginning of fatty acid biosynthesis by employing an [14C]-acp loading assay. Surprisingly, acpP remained functional even after heat treatment at 95°C for up to 10 min. NMR data from 2D-HSQC experiments as well as interaction studies with acpS confirmed that acpP is structured and active both before and after heat treatment, with no significant differences between the two. Thus, our data suggest that S. aureus acpP is a highly stable protein capable of maintaining its structure at high temperatures.

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Li, S., L. Lei, C. R. Somerville, and Y. Gu. "Cellulose synthase interactive protein 1 (CSI1) links microtubules and cellulose synthase complexes." Proceedings of the National Academy of Sciences 109, no. 1 (December 21, 2011): 185–90. http://dx.doi.org/10.1073/pnas.1118560109.

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IEMURA, Shun-ichiro, and Tohru NATSUME. "A systematic analysis of protein interaction networks leading to the drug discovery." Synthesiology English edition 1, no. 2 (2008): 114–20. http://dx.doi.org/10.5571/syntheng.1.114.

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Zhu, Xiaoyu, Shundai Li, Songqin Pan, Xiaoran Xin, and Ying Gu. "CSI1, PATROL1, and exocyst complex cooperate in delivery of cellulose synthase complexes to the plasma membrane." Proceedings of the National Academy of Sciences 115, no. 15 (March 26, 2018): E3578—E3587. http://dx.doi.org/10.1073/pnas.1800182115.

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Cellulose synthesis occurs exclusively at the plasma membrane by cellulose synthase complexes (CSCs). Therefore, delivery of CSCs to discrete sites at the plasma membrane is critical for cellulose synthesis. Despite their significance, the delivery of CSCs is poorly understood. Here we used proteomics approaches, functional genetics, and live cell imaging to show that the de novo secretion of CSCs is mediated by cooperation among cellulose synthase interactive 1 (CSI1), the plant-specific protein PATROL1, and exocyst complex in Arabidopsis thaliana. We propose that CSI1 plays a role in marking the docking site, which allows CSCs-containing vesicles access to the plasma membrane through its interaction with microtubules. PATROL1 assists in exocytosis by its interaction with multiple components, including CSI1, CSCs, and exocyst subunits. Both PATROL1 and the exocyst complex determine the rate of delivery of CSCs to the plasma membrane. By monitoring the exocyst complex, PATROL1, CSI1, and CSCs dynamics in real time, we present a timeline of events for exocytosis of CSCs. Our findings provide unique insights into the evolution of exocytosis in eukaryotes.

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Osipov, Stepan D., Yury L. Ryzhykau, Egor V. Zinovev, Andronika V. Minaeva, Sergey D. Ivashchenko, Dmitry P. Verteletskiy, Vsevolod V. Sudarev, et al. "I-Shaped Dimers of a Plant Chloroplast FOF1-ATP Synthase in Response to Changes in Ionic Strength." International Journal of Molecular Sciences 24, no. 13 (June 27, 2023): 10720. http://dx.doi.org/10.3390/ijms241310720.

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F-type ATP synthases play a key role in oxidative and photophosphorylation processes generating adenosine triphosphate (ATP) for most biochemical reactions in living organisms. In contrast to the mitochondrial FOF1-ATP synthases, those of chloroplasts are known to be mostly monomers with approx. 15% fraction of oligomers interacting presumably non-specifically in a thylakoid membrane. To shed light on the nature of this difference we studied interactions of the chloroplast ATP synthases using small-angle X-ray scattering (SAXS) method. Here, we report evidence of I-shaped dimerization of solubilized FOF1-ATP synthases from spinach chloroplasts at different ionic strengths. The structural data were obtained by SAXS and demonstrated dimerization in response to ionic strength. The best model describing SAXS data was two ATP-synthases connected through F1/F1′ parts, presumably via their δ-subunits, forming “I” shape dimers. Such I-shaped dimers might possibly connect the neighboring lamellae in thylakoid stacks assuming that the FOF1 monomers comprising such dimers are embedded in parallel opposing stacked thylakoid membrane areas. If this type of dimerization exists in nature, it might be one of the pathways of inhibition of chloroplast FOF1-ATP synthase for preventing ATP hydrolysis in the dark, when ionic strength in plant chloroplasts is rising. Together with a redox switch inserted into a γ-subunit of chloroplast FOF1 and lateral oligomerization, an I-shaped dimerization might comprise a subtle regulatory process of ATP synthesis and stabilize the structure of thylakoid stacks in chloroplasts.

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Su, Zenghua, Michael A. Blazing, Daju Fan, and Samuel E. George. "The Calmodulin-Nitric Oxide Synthase Interaction." Journal of Biological Chemistry 270, no. 49 (December 8, 1995): 29117–22. http://dx.doi.org/10.1074/jbc.270.49.29117.

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Sumegi, B., H. F. Gilbert, and P. A. Srere. "Interaction between citrate synthase and thiolase." Journal of Biological Chemistry 260, no. 1 (January 1985): 188–90. http://dx.doi.org/10.1016/s0021-9258(18)89713-7.

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Skurat, Alexander V., Amy D. Dietrich, and Peter J. Roach. "Interaction between glycogenin and glycogen synthase." Archives of Biochemistry and Biophysics 456, no. 1 (December 2006): 93–97. http://dx.doi.org/10.1016/j.abb.2006.09.024.

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Gorska-Ponikowska, Magdalena, Alicja Kuban-Jankowska, Antonella Marino Gammazza, Agnieszka Daca, Justyna M. Wierzbicka, Michal A. Zmijewski, Hue H. Luu, Michal Wozniak, and Francesco Cappello. "The Major Heat Shock Proteins, Hsp70 and Hsp90, in 2-Methoxyestradiol-Mediated Osteosarcoma Cell Death Model." International Journal of Molecular Sciences 21, no. 2 (January 17, 2020): 616. http://dx.doi.org/10.3390/ijms21020616.

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2-Methoxyestradiol is one of the natural 17β-estradiol derivatives and a potential novel anticancer agent currently being under evaluation in advanced phases of clinical trials. However, the mechanism of anticancer action of 2-methoxyestradiol has not been yet fully established. In our previous studies we have demonstrated that 2-methoxyestradiol selectively induces the expression and nuclear translocation of neuronal nitric oxide synthase in osteosarcoma 143B cells. Heat shock proteins (Hsps) are factors involved in the regulation of expression and activity of nitric oxide synthases. Herein, we chose osteosarcoma cell lines differed in metastatic potential, metastatic 143B and highly metastatic MG63.2 cells, in order to further investigate the anticancer mechanism of 2-methoxyestradiol. The current study aimed to determine the role of major heat shock proteins, Hsp90 and Hsp70 in 2-methoxyestradiol-induced osteosarcoma cell death. We focused on the implication of Hsp90 and Hsp70 in control under expression of neuronal nitric oxide synthase, localization of the enzyme, and further generation of nitro-oxidative stress. To give the insight into the role of Hsp90 in regulation of anticancer efficacy of 2-methoxyestradiol, we used geldanamycin as a potent Hsp90 inhibitor. Herein, we evidenced that inhibition of Hsp90 controls the protein expression of 2-methoxyestradiol-induced neuronal nitric oxide synthase and inhibits enzyme nuclear translocation. We propose that decreased level of neuronal nitric oxide synthase protein after a combined treatment with 2-methoxyestradiol and geldanamycin is directly associated with the accompanying upregulation of Hsp70 and downregulation of Hsp90. This interaction resulted in abrogation of anticancer efficacy of 2-methoxyestradiol by geldanamycin.

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Claypool, Steven M., Pinmanee Boontheung, J. Michael McCaffery, Joseph A. Loo, and Carla M. Koehler. "The Cardiolipin Transacylase, Tafazzin, Associates with Two Distinct Respiratory Components Providing Insight into Barth Syndrome." Molecular Biology of the Cell 19, no. 12 (December 2008): 5143–55. http://dx.doi.org/10.1091/mbc.e08-09-0896.

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Mutations in the mitochondrial cardiolipin (CL) transacylase, tafazzin (Taz1p), result in the X-linked cardioskeletal myopathy, Barth syndrome (BTHS). The mitochondria of BTHS patients exhibit variable respiratory defects and abnormal cristae ultrastructure. The biochemical basis for these observations is unknown. In the absence of its target phospholipid, CL, a very large Taz1p complex is missing, whereas several discrete smaller complexes are still observed. None of the identified Taz1p complexes represents Taz1p homodimers. Instead, yeast Taz1p physically assembles in several protein complexes of distinct size and composition. The ATP synthase and AAC2, both required for oxidative phosphorylation, are identified in separate stable Taz1p complexes. In the absence of CL, each interaction is still detected albeit in reduced abundance compared with when CL is present. Taz1p is not necessary for the normal expression of AAC2 or ATP synthase subunits or assembly of their respective complexes. In contrast, the largest Taz1p complex requires assembled ATP synthase and CL. Mitochondria in Δtaz1 yeast, similar to ATP synthase oligomer mutants, exhibit altered cristae morphology even though ATP synthase oligomer formation is unaffected. Thus, the Taz1p interactome defined here provides novel insight into the variable respiratory defects and morphological abnormalities observed in mitochondria of BTHS patients.

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Malathi, K., Y. Xiao, and A. P. Mitchell. "Interaction of yeast repressor-activator protein Ume6p with glycogen synthase kinase 3 homolog Rim11p." Molecular and Cellular Biology 17, no. 12 (December 1997): 7230–36. http://dx.doi.org/10.1128/mcb.17.12.7230.

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Meiosis and expression of early meiotic genes in the budding yeast Saccharomyces cerevisiae depend upon Rim11p, Ume6p, and Ime1p. Rim11p (also called Mds1p and ScGSK3) is a protein kinase related to glycogen synthase kinase 3 (GSK3); Ume6p is an architectural transcription factor; and Imelp is a Ume6p-binding protein that provides a transcriptional activation domain. Rim11p is required for Ime1p-Ume6p interaction, and prior studies have shown that Rim11p binds to and phosphorylates Ime1p. We show here that Rim11p binds to and phosphorylates Ume6p, as well. Amino acid substitutions in Ume6p that alter a consensus GSK3 site reduce or abolish Rim11p-Ume6p interaction and Rim11p-dependent phosphorylation, and they cause defects in interaction between Ume6p and Ime1p and in meiotic gene expression. Therefore, interaction between Rim11p and Ume6p, resulting in phosphorylation of Ume6p, is required for Ime1p-Ume6p complex formation. Rim11p, like metazoan GSK3beta, phosphorylates both interacting subunits of a target protein complex.

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Hyndman, Mathew Eric, Subodh Verma, Robin J. Rosenfeld, Todd J. Anderson, and Howard G. Parsons. "Interaction of 5-methyltetrahydrofolate and tetrahydrobiopterin on endothelial function." American Journal of Physiology-Heart and Circulatory Physiology 282, no. 6 (June 1, 2002): H2167—H2172. http://dx.doi.org/10.1152/ajpheart.00935.2001.

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The present study was designed to investigate the interaction between 5-methyltetrahydrofolate and tetrahydrobiopterin in modulating endothelial function. Tetrahydrobiopterin is a critical cofactor for nitric oxide synthase and maintains this enzyme as a nitric oxide- versus superoxide-producing enzyme. The structure of 5-methyltetrahydrofolate is similar to tetrahydrobiopterin and both agents have been shown to improve endothelium-dependent vasodilatation. We hypothesized that 5-methyltetrahydrofolate interacts with nitric oxide synthase in a fashion analogous, yet independent, of tetrahydrobiopterin to improve endothelial function. We demonstrate that 5-methyltetrahydrofolate binds the active site of nitric oxide synthase and mimics the orientation of tetrahydrobiopterin. Furthermore, 5-methyltetrahydrofolate attenuates superoxide production (induced by inhibition of tetrahydrobiopterin synthesis) and improves endothelial function in aortae isolated from tetrahydrobiopterin-deficient rats. We suggest that 5-methyltetrahydrofolate directly interacts with nitric oxide synthase to promote nitric oxide (vs. superoxide) production and improve endothelial function. 5-Methyltetrahydrofolate may represent an important strategy for intervention aimed at improving tetrahydrobiopterin bioavailability.

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Fenton, Andrew K., Sylvie Manuse, Josué Flores-Kim, Pierre Simon Garcia, Chryslène Mercy, Christophe Grangeasse, Thomas G. Bernhardt, and David Z. Rudner. "Phosphorylation-dependent activation of the cell wall synthase PBP2a in Streptococcus pneumoniae by MacP." Proceedings of the National Academy of Sciences 115, no. 11 (February 27, 2018): 2812–17. http://dx.doi.org/10.1073/pnas.1715218115.

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Most bacterial cells are surrounded by an essential cell wall composed of the net-like heteropolymer peptidoglycan (PG). Growth and division of bacteria are intimately linked to the expansion of the PG meshwork and the construction of a cell wall septum that separates the nascent daughter cells. Class A penicillin-binding proteins (aPBPs) are a major family of PG synthases that build the wall matrix. Given their central role in cell wall assembly and importance as drug targets, surprisingly little is known about how the activity of aPBPs is controlled to properly coordinate cell growth and division. Here, we report the identification of MacP (SPD_0876) as a membrane-anchored cofactor of PBP2a, an aPBP synthase of the Gram-positive pathogen Streptococcus pneumoniae. We show that MacP localizes to the division site of S. pneumoniae, forms a complex with PBP2a, and is required for the in vivo activity of the synthase. Importantly, MacP was also found to be a substrate for the kinase StkP, a global cell cycle regulator. Although StkP has been implicated in controlling the balance between the elongation and septation modes of cell wall synthesis, none of its substrates are known to modulate PG synthetic activity. Here we show that a phosphoablative substitution in MacP that blocks StkP-mediated phosphorylation prevents PBP2a activity without affecting the MacP–PBP2a interaction. Our results thus reveal a direct connection between PG synthase function and the control of cell morphogenesis by the StkP regulatory network.

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Voeller, Donna M., Li-ming Changchien, Gladys F. Maley, Frank Maley, Teiji Takechi, Ross E. Turner, William R. Montfort, Carmen J. Allegra, and Edward Chu. "Characterization of a specific interaction betweenEscherichia colithymidylate synthase andEscherichia colithymidylate synthase mRNA." Nucleic Acids Research 23, no. 5 (1995): 869–75. http://dx.doi.org/10.1093/nar/23.5.869.

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Amore, A., R. Bonaudo, D. Ghigo, M. Arese, C. Costamagna, P. Cirina, B. Gianoglio, L. Perugini, and R. Coppo. "Enhanced production of nitric oxide by blood-dialysis membrane interaction." Journal of the American Society of Nephrology 6, no. 4 (October 1995): 1278–83. http://dx.doi.org/10.1681/asn.v641278.

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Nitric oxide (NO) is a powerful vasoactive product of endothelial origin, and one of its major effects is vasodilation, leading to hypotension. The role of NO in some complications of uremia is still debated. This study evaluated whether endothelial NO synthase activity could be modulated by the exposure of healthy blood to hemodialysis materials. In vitro hemodialysis sessions were performed with cuprophan and polymethylmethacrylate membranes. Blood samples from a healthy donor after recirculation for 0, 5, 15, 30, and 60 min were coincubated for 6 h with a murine endothelial cell line (t.End.1); mRNA for inducible NO synthase and enzyme activity, measured as (3H)citrulline produced from (3H)arginine, were detected. The release of interleukin (IL)-1 beta and tumor necrosis factor-alpha (TNF-alpha) from recirculating lymphomonocytes was measured, too. The NO synthase activity of endothelial cells was stimulated by blood dialyzed with cuprophan, peaking at 15 min (11-fold increase in comparison to the basal values), whereas polymethylmethacrylate was ineffective (P < 0.01 versus Cuprophan). Dialysis with cuprophan, but not with polymethylmethacrylate, induced in endothelial cells the expression of mRNA encoding for inducible NO synthase. The release of IL-1 beta and TNF-alpha after 6 h by recirculating lymphomonocytes paralleled the NO synthase activity profile in endothelial cells and was significantly higher after cuprophan exposure than after polymethylmethacrylate (P < 0.0001). In conclusion, the activity of endothelial NO synthase can be enhanced during the dialysis sessions by the interaction of lymphomonocytes with the membranes, possibly via TNF-alpha and IL-1 beta production.

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DeMarini, Douglas J., Alison E. M. Adams, Hanna Fares, Claudio De Virgilio, Giorgio Valle, John S. Chuang, and John R. Pringle. "A Septin-based Hierarchy of Proteins Required for Localized Deposition of Chitin in the Saccharomyces cerevisiae Cell Wall." Journal of Cell Biology 139, no. 1 (October 6, 1997): 75–93. http://dx.doi.org/10.1083/jcb.139.1.75.

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Just before bud emergence, a Saccharomyces cerevisiae cell forms a ring of chitin in its cell wall; this ring remains at the base of the bud as the bud grows and ultimately forms part of the bud scar marking the division site on the mother cell. The chitin ring seems to be formed largely or entirely by chitin synthase III, one of the three known chitin synthases in S. cerevisiae. The chitin ring does not form normally in temperature-sensitive mutants defective in any of four septins, a family of proteins that are constituents of the “neck filaments” that lie immediately subjacent to the plasma membrane in the mother-bud neck. In addition, a synthetic-lethal interaction was found between cdc12-5, a temperature-sensitive septin mutation, and a mutant allele of CHS4, which encodes an activator of chitin synthase III. Two-hybrid analysis revealed no direct interaction between the septins and Chs4p but identified a novel gene, BNI4, whose product interacts both with Chs4p and Cdc10p and with one of the septins, Cdc10p; this analysis also revealed an interaction between Chs4p and Chs3p, the catalytic subunit of chitin synthase III. Bni4p has no known homologues; it contains a predicted coiled-coil domain, but no other recognizable motifs. Deletion of BNI4 is not lethal, but causes delocalization of chitin deposition and aberrant cellular morphology. Overexpression of Bni4p also causes delocalization of chitin deposition and produces a cellular morphology similar to that of septin mutants. Immunolocalization experiments show that Bni4p localizes to a ring at the mother-bud neck that lies predominantly on the mother-cell side (corresponding to the predominant site of chitin deposition). This localization depends on the septins but not on Chs4p or Chs3p. A GFP-Chs4p fusion protein also localizes to a ring at the mother-bud neck on the mother-cell side. This localization is dependent on the septins, Bni4p, and Chs3p. Chs3p, whose normal localization is similar to that of Chs4p, does not localize properly in bni4, chs4, or septin mutant strains or in strains that accumulate excess Bni4p. In contrast, localization of the septins is essentially normal in bni4, chs4, and chs3 mutant strains and in strains that accumulate excess Bni4p. Taken together, these results suggest that the normal localization of chitin synthase III activity is achieved by assembly of a complex in which Chs3p is linked to the septins via Chs4p and Bni4p.

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Peluso, John J., Xiufang Liu, and Jonathan Romak. "Progesterone Maintains Basal Intracellular Adenosine Triphosphate Levels and Viability of Spontaneously Immortalized Granulosa Cells by Promoting an Interaction between 14-3-3σ and ATP Synthaseβ/Precursor through a Protein Kinase G-Dependent Mechanism." Endocrinology 148, no. 5 (May 1, 2007): 2037–44. http://dx.doi.org/10.1210/en.2006-1603.

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The present studies were designed to 1) describe changes in both the mitochondrial membrane potential and ATP content of spontaneously immortalized granulosa cells as they undergo apoptosis, 2) identify some of the downstream events that are activated by progesterone (P4), and 3) relate these downstream events to changes in mitochondrial function and apoptotic cell death. These studies revealed that in response to serum deprivation, the mitochondrial membrane potential initially hyperpolarizes and ATP content increases. That this increase in ATP is required for apoptosis was demonstrated by the finding that oligomycin inhibited the increase in ATP and apoptosis. Piridoxalphosphate-6-azopeyl-2′-4′-disulfonic acid, an inhibitor of purinergic receptors, which are activated by ATP, also inhibited apoptosis due to serum withdrawal. This study provides additional support for ATP’s causative role in apoptosis. Moreover, 8-Br-cGMP, a protein kinase G (PKG) activator, mimicked P4’s action, whereas a PKG antagonist, DT-3, attenuated P4’s suppressive effect on ATP and apoptosis. Finally, DT-3 treatment was shown to attenuate P4-regulated phosphorylation of 14-3-3σ and its binding partner, ATP synthaseβ/precursor and the amount of ATP synthaseβ/precursor that bound to 14-3-3σ. Based on these data, it is proposed that P4 prevents apoptosis in part by activating PKG, which in turn maintains the interaction between ATP synthaseβ/precursor and 14-3-3σ. In the absence of P4-induced PKG activity, we further propose that some ATP synthaseβ precursor dissociates from 14-3-3σ, resulting in its activation and incorporation into the ATP synthase complex, which ultimately results in an increase in ATP and apoptosis.

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He, Jun, Richard A. Fandino, Rayko Halitschke, Katrin Luck, Tobias G. Köllner, Mark H. Murdock, Rishav Ray, et al. "An unbiased approach elucidates variation in (S)-(+)-linalool, a context-specific mediator of a tri-trophic interaction in wild tobacco." Proceedings of the National Academy of Sciences 116, no. 29 (July 1, 2019): 14651–60. http://dx.doi.org/10.1073/pnas.1818585116.

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Plant volatile organic compounds (VOCs) mediate many interactions, and the function of common VOCs is especially likely to depend on ecological context. We used a genetic mapping population of wild tobacco, Nicotiana attenuata, originating from a cross of 2 natural accessions from Arizona and Utah, separated by the Grand Canyon, to dissect genetic variation controlling VOCs. Herbivory-induced leaf terpenoid emissions varied substantially, while green leaf volatile emissions were similar. In a field experiment, only emissions of linalool, a common VOC, correlated significantly with predation of the herbivore Manduca sexta by native predators. Using quantitative trait locus mapping and genome mining, we identified an (S)-(+)-linalool synthase (NaLIS). Genome resequencing, gene cloning, and activity assays revealed that the presence/absence of a 766-bp sequence in NaLIS underlies the variation of linalool emissions in 26 natural accessions. We manipulated linalool emissions and composition by ectopically expressing linalool synthases for both enantiomers, (S)-(+)- and (R)-(−)-linalool, reported to oppositely affect M. sexta oviposition, in the Arizona and Utah accessions. We used these lines to test ovipositing moths in increasingly complex environments. The enantiomers had opposite effects on oviposition preference, but the magnitude of the effect depended strongly both on plant genetic background, and complexity of the bioassay environment. Our study reveals that the emission of linalool, a common VOC, differs by orders-of-magnitude among geographically interspersed conspecific plants due to allelic variation in a linalool synthase, and that the response of a specialist herbivore to linalool depends on enantiomer, plant genotype, and environmental complexity.

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Zhao, Zhiguang, Guocang Chen, and Chenglie Zhang. "Interaction between reactive oxygen species and nitric oxide in drought-induced abscisic acid synthesis in root tips of wheat seedlings." Functional Plant Biology 28, no. 10 (2001): 1055. http://dx.doi.org/10.1071/pp00143.

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Abscisic acid accumulation and oxidative stress are two common responses of plants to environmental stresses. However, little is known about their relationships. The purpose of this article is to investigate the effects of reactive oxygen species and nitric oxide on the plant hormone abscisic acid synthesis in root tips of wheat (Triticum aestivum L.) seedlings under drought stress. Detached root tips were subjected to drought stress by naturally evaporating until 20% of their fresh weights were lost. The activities of superoxide synthases and nitric oxide synthase (EC 1.14.13.39) increased after 20 min of treatment and abscisic acid began to accumulate 60 min later. The induction of abscisic acid by drought was strongly blocked by pretreating the root tips with reactive oxygen species eliminators tiron or ascorbate acid, and with nitric oxide synthase inhibitor Nω-nitro-L-arginine or nitric oxide eliminator 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl 3-oxide. Consistent with these results, reactive oxygen species generators diethyldithiocarbamic acid, xanthine–xanthine oxidase and triazole or nitric oxide donor sodium nitroprusside can also induce abscisic acid accumulation in root tips of wheat seedlings. While potentiated by reactive oxygen species, the effect of sodium nitroprusside on abscisic acid accumulation was blocked by 2-phenyl-4,4,5,5-tetramethyl-imidazoline-1-oxyl 3-oxide. Based on these results, we suggest that reactive oxygen species and nitric oxide play important roles in drought-induced abscisic acid synthesis in plant, they may be the signals through which the plant can ‘sense’ the drought condition.

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Gnedenko, O. V., E. O. Yablokov, P. V. Ershov, A. V. Svirid, T. V. Shkel, I. V. Haidukevich, N. V. Strushkevich, A. A. Gilep, S. A. Usanov, and A. S. Ivanov. "Interaction of prostacyclin synthase with cytochromes P450." Biomeditsinskaya Khimiya 65, no. 1 (January 2019): 63–66. http://dx.doi.org/10.18097/pbmc20196501063.

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Biosensor experiments on investigation of interaction between prostacyclin synthase (PGIS) and different proteins of the cytochrome P450 monooxygenase systems were perfomed. Interaction of PGIS with microsomal (CYP21A2, CYP2E1) and mitochondrial (CYP27A1, CYP11B1, CYP11B2, CYP11A1) cytochrome P450s was detected. Kinetic and equilibrium parameters of protein complexes formation were determined. Data obtained suggest an essential role of these hemoproteins interaction in regulation of prostacyclin and thromboxane A2 biosynthesis.

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Morgunov, Igor, and Paul A. Srere. "Interaction between Citrate Synthase and Malate Dehydrogenase." Journal of Biological Chemistry 273, no. 45 (November 6, 1998): 29540–44. http://dx.doi.org/10.1074/jbc.273.45.29540.

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Zebarjadian, Yeganeh, Tom King, Maurille J. Fournier, Louise Clarke, and John Carbon. "Point Mutations in Yeast CBF5 Can Abolish In Vivo Pseudouridylation of rRNA." Molecular and Cellular Biology 19, no. 11 (November 1, 1999): 7461–72. http://dx.doi.org/10.1128/mcb.19.11.7461.

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ABSTRACT In budding yeast (Saccharomyces cerevisiae), the majority of box H/ACA small nucleolar RNPs (snoRNPs) have been shown to direct site-specific pseudouridylation of rRNA. Among the known protein components of H/ACA snoRNPs, the essential nucleolar protein Cbf5p is the most likely pseudouridine (Ψ) synthase. Cbf5p has considerable sequence similarity to Escherichia coli TruBp, a known Ψ synthase, and shares the “KP” and “XLD” conserved sequence motifs found in the catalytic domains of three distinct families of known and putative Ψ synthases. To gain additional evidence on the role of Cbf5p in rRNA biosynthesis, we have used in vitro mutagenesis techniques to introduce various alanine substitutions into the putative Ψ synthase domain of Cbf5p. Yeast strains expressing these mutatedcbf5 genes in a cbf5Δ null background are viable at 25°C but display pronounced cold- and heat-sensitive growth phenotypes. Most of the mutants contain reduced levels of Ψ in rRNA at extreme temperatures. Substitution of alanine for an aspartic acid residue in the conserved XLD motif of Cbf5p (mutantcbf5D95A) abolishes in vivo pseudouridylation of rRNA. Some of the mutants are temperature sensitive both for growth and for formation of Ψ in the rRNA. In most cases, the impaired growth phenotypes are not relieved by transcription of the rRNA from a polymerase II-driven promoter, indicating the absence of polymerase I-related transcriptional defects. There is little or no abnormal accumulation of pre-rRNAs in these mutants, although preferential inhibition of 18S rRNA synthesis is seen in mutantcbf5D95A, which lacks Ψ in rRNA. A subset of mutations in the Ψ synthase domain impairs association of the altered Cbf5p proteins with selected box H/ACA snoRNAs, suggesting that the functional catalytic domain is essential for that interaction. Our results provide additional evidence that Cbf5p is the Ψ synthase component of box H/ACA snoRNPs and suggest that the pseudouridylation of rRNA, although not absolutely required for cell survival, is essential for the formation of fully functional ribosomes.

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Ju, Hong, Rong Zou, Virginia J. Venema, and Richard C. Venema. "Direct Interaction of Endothelial Nitric-oxide Synthase and Caveolin-1 Inhibits Synthase Activity." Journal of Biological Chemistry 272, no. 30 (July 25, 1997): 18522–25. http://dx.doi.org/10.1074/jbc.272.30.18522.

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Li, Zhong, Muhammad Umar Khan, Xue Yan, Dan Mu, Yuebin Xie, Muhammad Waqas, Xin Wu, Puleng Letuma, Changxun Fang, and Wenxiong Lin. "Deciphering the Molecular Mechanisms of Chilling Tolerance in Lsi1-Overexpressing Rice." International Journal of Molecular Sciences 23, no. 9 (April 23, 2022): 4667. http://dx.doi.org/10.3390/ijms23094667.

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Improving tolerance to low-temperature stress during the rice seedling stage is of great significance in agricultural science. In this study, using the low silicon gene 1 (Lsi1)-overexpressing (Dular-OE) and wild-type rice (Dular-WT), we showed that Lsi1 overexpression enhances chilling tolerance in Dular-OE. The overexpression of the Lsi1 increases silicon absorption, but it was not the main reason for chilling tolerance in Dular-OE. Instead, our data suggest that the overexpression of a Lsi1-encoding NIP and its interaction with key proteins lead to chilling tolerance in Dular-OE. Additionally, we show that the high-mobility group protein (HMG1) binds to the promoter of Lsi1, positively regulating its expression. Moreover, Nod26-like major intrinsic protein (NIP)’s interaction with α and β subunits of ATP synthase and the 14-3-3f protein was validated by co-immunoprecipitation (Co-IP), bimolecular fluorescent complementary (BiFC), and GST-pulldown assays. Western blotting revealed that the overexpression of NIP positively regulates the ATP-synthase subunits that subsequently upregulate calcineurin B-like interacting protein kinases (CIPK) negatively regulating 14-3-3f. Overall, these NIP-mediated changes trigger corresponding pathways in an orderly manner, enhancing chilling tolerance in Dular-OE.

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Raff, H., and B. Jankowski. "Inhibition of aldosterone release by hypoxia in vitro: interaction with carbon monoxide." Journal of Applied Physiology 76, no. 2 (February 1, 1994): 689–93. http://dx.doi.org/10.1152/jappl.1994.76.2.689.

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We have demonstrated that the aldosteronogenic pathway of the zona glomerulosa is unusually sensitive to modest changes in PO2 (Michaelis constant for O2 approximately 95 Torr). The current study evaluated the interaction of CO (the classic ligand for P-450 enzymes) and the decreases in O2 on aldosteronogenesis in vitro. Bovine adrenocortical zona glomerulosa cells were incubated for 2 h and stimulated with either adenosine 3′,5′-cyclic monophosphate (cAMP) or angiotensin II. Ten and 20% CO led to significant decreases in cAMP- and angiotensin II-stimulated aldosteronogenesis. The combination of 20% CO and moderate decreases in PO2 (from approximately 140 to approximately 100 Torr) led to an interactive decrease in aldosterone production. The conversion of corticosterone to aldosterone catalyzed by aldosterone synthase, which is the site of O2 sensitivity, was not significantly inhibited by CO. We conclude that the aldosterone pathway is not exceptionally sensitive to CO compared with other steroidogenic pathways. This observation suggests that the unique O2-sensitive properties of the aldosterone pathway located primarily within aldosterone synthase may not reside in its CO binding site (i.e., heme).

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Kluijtmans, Leo A. J., Ian S. Young, Colin A. Boreham, Liam Murray, Dorothy McMaster, Helene McNulty, J. J. Strain, Joseph McPartlin, John M. Scott, and Alexander S. Whitehead. "Genetic and nutritional factors contributing to hyperhomocysteinemia in young adults." Blood 101, no. 7 (April 1, 2003): 2483–88. http://dx.doi.org/10.1182/blood.v101.7.2483.

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A modestly elevated total plasma homocysteine concentration (tHcy) is generally accepted as an independent and graded risk factor for various pathologies, including vascular diseases, neural tube defects, Alzheimer disease, and pregnancy complications. We analyzed 5 common functional polymorphisms in enzymes involved in homocysteine metabolism (ie, methylenetetrahydrofolate reductase [MTHFR] 677C>T and 1298A>C, methionine synthase [MTR] 2756A>G, cystathionine β-synthase [CBS] 844ins68, and methionine synthase reductase [MTRR] 66A>G) in 452 young adults, and quantified their independent and interactive effects on tHcy concentrations. Serum folate, red cell folate, vitamin B12, and tHcy concentrations were significantly influenced by MTHFR 677C>T genotypes. A particularly strong interaction was observed between theMTHFR 677TT genotype and serum folate, which led to a high tHcy phenotype that was more pronounced in males. The genetic contribution to the variance in tHcy was estimated to be approximately 9%, compared with approximately 35% that could be attributed to low folate and vitamin B12. Our study indicates that dietary factors are centrally important in the control of tHcy levels in young adults with additional, but somewhat weaker, genetic effects. These data underscore the potential benefits that may be gained by improving the dietary status of young adults, and provide support for the implementation of folate/B-vitamin food fortification programs.

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Walters, Jewell N., Justin S. Bickford, Kimberly J. Newsom, Dawn E. Beachy, Sarah J. Barilovits, John-David Herlihy, and Harry S. Nick. "Regulation of human microsomal prostaglandin E synthase-1 by IL-1β requires a distal enhancer element with a unique role for C/EBPβ." Biochemical Journal 443, no. 2 (March 27, 2012): 561–71. http://dx.doi.org/10.1042/bj20111801.

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The studies of PGE2 (prostaglandin E2) biosynthesis have focused primarily on the role of cyclo-oxygenases. Efforts have shifted towards the specific PGE2 terminal synthases, particularly mPGES-1 (microsomal PGE synthase 1), which has emerged as the crucial inducible synthase with roles in pain, cancer and inflammation. mPGES-1 is induced by pro-inflammatory cytokines with studies focusing on the proximal promoter, mediated specifically through Egr-1 (early growth-response factor 1). Numerous studies demonstrate that the mPGES-1 promoter (PTGES) alone cannot account for the level of IL-1β (interleukin 1β) induction. We identified two DNase I-hypersensitive sites within the proximal promoter near the Egr-1 element and a novel distal site near −8.6 kb. Functional analysis of the distal site revealed two elements that co-operate with basal promoter expression and a stimulus-dependent enhancer. A specific binding site for C/EBPβ (CCAAT/enhancer-binding protein β) in the enhancer was directly responsible for inducible enhancer activity. ChIP (chromatin immunoprecipitation) analysis demonstrated constitutive Egr-1 binding to the promoter and induced RNA polymerase II and C/EBPβ binding to the promoter and enhancer respectively. Knockout/knockdown studies established a functional role for C/EBPβ in mPGES-1 gene regulation and the documented interaction between Egr-1 and C/EBPβ highlights the proximal promoter co-operation with a novel distal enhancer element in regulating inducible mPGES-1 expression.

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Ogasahara, K., M. Ishida, and K. Yutani. "Subunit-subunit interaction of tryptophan synthase from hyperthermophile." Seibutsu Butsuri 40, supplement (2000): S118. http://dx.doi.org/10.2142/biophys.40.s118_1.

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Wübert, Joachim, Ulrike Oster, and Wolfhart Rüdiger. "Interaction of 5-hydroxymethyl-furfural with hydroxymethylbilane synthase." Phytochemistry 46, no. 1 (September 1997): 45–50. http://dx.doi.org/10.1016/s0031-9422(97)00215-x.

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Hall, Diane A., Tuajuanda C. Jordan-Starck, Rachel O. Loo, Martha L. Ludwig, and Rowena G. Matthews. "Interaction of Flavodoxin with Cobalamin-Dependent Methionine Synthase†." Biochemistry 39, no. 35 (September 2000): 10711–19. http://dx.doi.org/10.1021/bi001096c.

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Tsai, A. L., C. H. Wei, and R. J. Kulmacz. "Interaction Between Nitric Oxide and Prostaglandin H Synthase." Archives of Biochemistry and Biophysics 313, no. 2 (September 1994): 367–72. http://dx.doi.org/10.1006/abbi.1994.1400.

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Cruz, Jorddy Neves, Sebastião Gomes Silva, Daniel Santiago Pereira, Antônio Pedro da Silva Souza Filho, Mozaniel Santana de Oliveira, Rafael Rodrigues Lima, and Eloisa Helena de Aguiar Andrade. "In Silico Evaluation of the Antimicrobial Activity of Thymol—Major Compounds in the Essential Oil of Lippia thymoides Mart. & Schauer (Verbenaceae)." Molecules 27, no. 15 (July 26, 2022): 4768. http://dx.doi.org/10.3390/molecules27154768.

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In this paper, we evaluated the drug-receptor interactions responsible for the antimicrobial activity of thymol, the major compound present in the essential oil (EO) of Lippia thymoides (L. thymoides) Mart. & Schauer (Verbenaceae). It was previously reported that this EO exhibits antimicrobial activity against Candida albicans (C. albicans), Staphylococcus aureus (S. aureus), and Escherichia coli (E. coli). Therefore, we used molecular docking, molecular dynamics simulations, and free energy calculations to investigate the interaction of thymol with pharmacological receptors of interest to combat these pathogens. We found that thymol interacted favorably with the active sites of the microorganisms’ molecular targets. MolDock Score results for systems formed with CYP51 (C. albicans), Dihydrofolate reductase (S. aureus), and Dihydropteroate synthase (E. coli) were −77.85, −67.53, and −60.88, respectively. Throughout the duration of the MD simulations, thymol continued interacting with the binding pocket of the molecular target of each microorganism. The van der Waals (ΔEvdW = −24.88, −26.44, −21.71 kcal/mol, respectively) and electrostatic interaction energies (ΔEele = −3.94, −11.07, −12.43 kcal/mol, respectively) and the nonpolar solvation energies (ΔGNP = −3.37, −3.25, −2.93 kcal/mol, respectively) were mainly responsible for the formation of complexes with CYP51 (C. albicans), Dihydrofolate reductase (S. aureus), and Dihydropteroate synthase (E. coli).

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Kuncewicz, Teresa, Priya Balakrishnan, Mark B. Snuggs, and Bruce C. Kone. "Specific association of nitric oxide synthase-2 with Rac isoforms in activated murine macrophages." American Journal of Physiology-Renal Physiology 281, no. 2 (August 1, 2001): F326—F336. http://dx.doi.org/10.1152/ajprenal.2001.281.2.f326.

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Nitric oxide synthase-2 (NOS2) is responsible for high-output nitric oxide production important in renal inflammation and injury. Using a yeast two-hybrid assay, we identified Rac2, a Rho GTPase member, as a NOS2-interacting protein. NOS2 and Rac2 proteins coimmunoprecipitated from activated RAW 264.7 macrophages. The two proteins colocalized in an intracellular compartment of these cells. Glutathione- S-transferase (GST) pull-down assays revealed that both Rac1 and Rac2 associated with GST-NOS2 and that the NOS2 oxygenase domain was necessary and sufficient for the interaction. [35S]methionine-labeled NOS2 interacted directly with GST-Rac2 in the absence of GTP, calmodulin, or NOS2 substrates or cofactors. Stable overexpression of Rac2 in RAW 264.7 cells augmented LPS-induced nitrite generation (∼60%) and NOS2 activity (∼45%) without measurably affecting NOS2 protein abundance and led to a redistribution of NOS2 to a high-speed Triton X-100-insoluble fraction. We conclude that Rac1 and Rac2 physically interact with NOS2 in activated macrophages and that the interaction with Rac2 correlates with a posttranslational stimulation of NOS2 activity and likely its spatial redistribution within the cell.

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Cui, Qiang. "Membrane-mediated interaction drives mitochondrial ATPase assembly and cristae formation." Journal of General Physiology 150, no. 6 (May 16, 2018): 777–80. http://dx.doi.org/10.1085/jgp.201812077.

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Burde, Tali, and Gilad Rimon. "On the interaction of specific prostaglandin H synthase-2 inhibitors with prostaglandin H synthase-1." European Journal of Pharmacology 453, no. 2-3 (October 2002): 167–73. http://dx.doi.org/10.1016/s0014-2999(02)02450-0.

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Garcia, Victor, Eon Joo Park, Mauro Siragusa, Florian Frohlich, Mohammad Mahfuzul Haque, Jonathan V. Pascale, Katherine R. Heberlein, Brant E. Isakson, Dennis J. Stuehr, and William C. Sessa. "Unbiased proteomics identifies plasminogen activator inhibitor-1 as a negative regulator of endothelial nitric oxide synthase." Proceedings of the National Academy of Sciences 117, no. 17 (April 16, 2020): 9497–507. http://dx.doi.org/10.1073/pnas.1918761117.

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Nitric oxide (NO) produced by endothelial nitric oxide synthase (eNOS) is a critical mediator of vascular function. eNOS is tightly regulated at various levels, including transcription, co- and posttranslational modifications, and by various protein–protein interactions. Using stable isotope labeling with amino acids in cell culture (SILAC) and mass spectrometry (MS), we identified several eNOS interactors, including the protein plasminogen activator inhibitor-1 (PAI-1). In cultured human umbilical vein endothelial cells (HUVECs), PAI-1 and eNOS colocalize and proximity ligation assays demonstrate a protein–protein interaction between PAI-1 and eNOS. Knockdown of PAI-1 or eNOS eliminates the proximity ligation assay (PLA) signal in endothelial cells. Overexpression of eNOS and HA-tagged PAI-1 in COS7 cells confirmed the colocalization observations in HUVECs. Furthermore, the source of intracellular PAI-1 interacting with eNOS was shown to be endocytosis derived. The interaction between PAI-1 and eNOS is a direct interaction as supported in experiments with purified proteins. Moreover, PAI-1 directly inhibits eNOS activity, reducing NO synthesis, and the knockdown or antagonism of PAI-1 increases NO bioavailability. Taken together, these findings place PAI-1 as a negative regulator of eNOS and disruptions in eNOS–PAI-1 binding promote increases in NO production and enhance vasodilation in vivo.

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47

Jia, Lixia, Mary K. Dienhart, and Rosemary A. Stuart. "Oxa1 Directly Interacts with Atp9 and Mediates Its Assembly into the Mitochondrial F1Fo-ATP Synthase Complex." Molecular Biology of the Cell 18, no. 5 (May 2007): 1897–908. http://dx.doi.org/10.1091/mbc.e06-10-0925.

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The yeast Oxa1 protein is involved in the biogenesis of the mitochondrial oxidative phosphorylation (OXPHOS) machinery. The involvement of Oxa1 in the assembly of the cytochrome oxidase (COX) complex, where it facilitates the cotranslational membrane insertion of mitochondrially encoded COX subunits, is well documented. In this study we have addressed the role of Oxa1, and its sequence-related protein Cox18/Oxa2, in the biogenesis of the F1Fo-ATP synthase complex. We demonstrate that Oxa1, but not Cox18/Oxa2, directly supports the assembly of the membrane embedded Fo-sector of the ATP synthase. Oxa1 was found to physically interact with newly synthesized mitochondrially encoded Atp9 protein in a posttranslational manner and in a manner that is not dependent on the C-terminal, matrix-localized region of Oxa1. The stable manner of the Atp9-Oxa1 interaction is in contrast to the cotranslational and transient interaction previously observed for the mitochondrially encoded COX subunits with Oxa1. In the absence of Oxa1, Atp9 was observed to assemble into an oligomeric complex containing F1-subunits, but its further assembly with subunit 6 (Atp6) of the Fo-sector was perturbed. We propose that by directly interacting with newly synthesized Atp9 in a posttranslational manner, Oxa1 is required to maintain the assembly competence of the Atp9-F1-subcomplex for its association with Atp6.

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Torgan, C. E., G. J. Etgen, J. T. Brozinick, R. E. Wilcox, and J. L. Ivy. "Interaction of aerobic exercise training and clenbuterol: effects on insulin-resistant muscle." Journal of Applied Physiology 75, no. 4 (October 1, 1993): 1471–76. http://dx.doi.org/10.1152/jappl.1993.75.4.1471.

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The effects of aerobic exercise training, chronic administration of the selective beta 2-adrenergic agonist clenbuterol, and the combination of these two treatments on muscle insulin resistance were compared in female obese (fa/fa) Zucker rats. Rats were randomly assigned to trained, clenbuterol, clenbuterol-trained, or control groups. Training consisted of treadmill running for 2 h/day at 18 m/min up an 8% grade. Clenbuterol was administered by intubation (0.4–0.8 mg.kg body wt-1 x day-1) approximately 30 min before the rats ran each day. After 8 wk of treatment, muscle insulin resistance was assessed via hindlimb perfusion in the presence of 8 mM glucose and a submaximal (500 microU/ml) insulin concentration. Training increased citrate synthase activity (mumol.g wet wt-1 x min-1) by 32–74% and insulin-stimulated glucose uptake by 45%. Clenbuterol ingestion induced a 17–29% increase in muscle mass but decreased citrate synthase activity by 34–42% and had no effect on muscle glucose uptake. Administration of clenbuterol to rats that exercise trained prevented the training-induced improvement in insulin-stimulated glucose uptake and attenuated the increases in citrate synthase activity. In addition, both clenbuterol-treated groups displayed a 42% decrease in beta-adrenergic receptor density. The results indicate that clenbuterol administration, possibly through beta-adrenergic receptor downregulation, attenuated a cellular reaction essential for the exercise training-induced increase in citrate synthase activity and improvement in skeletal muscle insulin resistance of the obese Zucker rat.

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Frost, David J., Kim Brandt, Tim Kaufmann, and Robert Goldman. "Interaction of sulfhydryl reactive reagents with components involved in (1,3)-β-glucan synthesis from Candida albicans." Canadian Journal of Microbiology 41, no. 8 (August 1, 1995): 692–98. http://dx.doi.org/10.1139/m95-095.

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Glucan synthesis was sensitive to several sulfhydryl reacting compounds: mercurials, reversible disulfides, and an alkylating sulfhydryl reagent (IC50 3–45 μM). Thiol groups associated with glucan synthesis were hydrophilic in nature, since both hydrophilic and hydrophobic reagents were active. Glucan synthase complex consists of at least two components: a peripheral GTP-binding protein that can be solubilized with detergents (supernatant) and the catalytic membrane-bound component (pellet). A rapid separation technique was developed to study sulfhydryl interactions with the complex. The GTP-binding protein was solubilized with 0.6% 3-((3-cholamidopropyl)dimethylammonio)-1-propane sulfonate from isolated microsomes of Candida albicans cells grown at either 10 or 30 °C. The residual membranous fraction contained the core catalytic moiety of glucan synthase. Both fractions were devoid of glucan synthase activity until they were reconstituted by mixing the two fractions together. In reconstitution experiments, the pellet lost almost 50% activity when preincubated with 2.5 μM N-ethylmaleimide and combined with an untreated supernatant whereas only 10% activity was lost when the supernatant was treated with N-ethylmaleimide. The catalytic active site of glucan synthase was not protected with UDP-Glc when preincubated with 10 μM N-ethylmaleimide but the GTP-binding fraction was partially protected with GTPγS.Key words: Candida albicans, (1,3)-β-glucan synthase, GTP-binding proteins, solubilization, sulfhydryl reagents.

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PETTERSON, Gosta, Ute LILL, and Hermann EGGERER. "Mechanism of interaction of citrate synthase with citryl-CoA." European Journal of Biochemistry 182, no. 1 (June 1989): 119–24. http://dx.doi.org/10.1111/j.1432-1033.1989.tb14807.x.

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Journal articles on the topic 'Synthese interactive'

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