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Full-Text Articles in Medicine and Health Sciences
Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou
Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou
Department of Biochemistry and Molecular Biology Faculty Papers
Trm5 is a eukaryal and archaeal tRNA methyltransferase that catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to the N(1) position of G37 directly 3' to the anticodon. While the biological role of m(1)G37 in enhancing translational fidelity is well established, the catalytic mechanism of Trm5 has remained obscure. To address the mechanism of Trm5 and more broadly the mechanism of N-methylation to nucleobases, we examined the pH-activity profile of an archaeal Trm5 enzyme, and performed structure-guided mutational analysis. The data reveal a marked dependence of enzyme-catalyzed methyl transfer on hydrogen ion equilibria: the single-turnover rate constant for methylation increases by one …
Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou
Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou
Department of Biochemistry and Molecular Biology Faculty Papers
Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …
Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou
Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou
Department of Biochemistry and Molecular Biology Faculty Papers
Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …
Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji
Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji
Department of Biochemistry and Molecular Biology Faculty Papers
After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a new round of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5gamma'-(beta,gamma-imido)triphosphate did not function at all. The k(cat) of eEF3 was 1.12 min(-1), which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated …
P66shc--A Longevity Redox Protein In Human Prostate Cancer Progression And Metastasis : P66shc In Cancer Progression And Metastasis., Mythilypriya Rajendran, Paul Thomes, Li Zhang, Suresh Veeramani, Ming-Fong Lin
P66shc--A Longevity Redox Protein In Human Prostate Cancer Progression And Metastasis : P66shc In Cancer Progression And Metastasis., Mythilypriya Rajendran, Paul Thomes, Li Zhang, Suresh Veeramani, Ming-Fong Lin
Journal Articles: Biochemistry & Molecular Biology
p66Shc, a 66 kDa proto-oncogene Src homologous-collagen homologue (Shc) adaptor protein, is classically known in mediating receptor tyrosine kinase signaling and recently identified as a sensor to oxidative stress-induced apoptosis and as a longevity protein in mammals. The expression of p66Shc is decreased in mice and increased in human fibroblasts upon aging and in aging-related diseases, including prostate cancer. p66Shc protein level correlates with the proliferation of several carcinoma cells and can be regulated by steroid hormones. Recent advances point that p66Shc protein plays a role in mediating cross-talk between steroid hormones and redox signals by serving as a common …
Structure Of Vibrio Cholerae Toxt Reveals A Mechanism For Fatty Acid Regulation Of Virulence Genes, Michael J. Lowden, Karen Skorupski, Maria Pellegrini, Michael G. Chiorazzo, Ronald K. Taylor, F. Jon Kull
Structure Of Vibrio Cholerae Toxt Reveals A Mechanism For Fatty Acid Regulation Of Virulence Genes, Michael J. Lowden, Karen Skorupski, Maria Pellegrini, Michael G. Chiorazzo, Ronald K. Taylor, F. Jon Kull
Dartmouth Scholarship
Cholera is an acute intestinal infection caused by the bacterium Vibrio cholerae. In order for V. cholerae to cause disease, it must produce two virulence factors, the toxin-coregulated pilus (TCP) and cholera toxin (CT), whose expression is controlled by a transcriptional cascade culminating with the expression of the AraC-family regulator, ToxT. We have solved the 1.9 A resolution crystal structure of ToxT, which reveals folds in the N- and C-terminal domains that share a number of features in common with AraC, MarA, and Rob as well as the unexpected presence of a buried 16-carbon fatty acid, cis-palmitoleate. The finding that …