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Full-Text Articles in Medicine and Health Sciences
Structural Basis For +1 Ribosomal Frameshifting During Ef-G-Catalyzed Translocation., Gabriel Demo, Howard Gamper, Anna B. Loveland, Isao Masuda, Christine E. Carbone, Egor Svidritskiy, Ya-Ming Hou, Andrei A. Korostelev
Structural Basis For +1 Ribosomal Frameshifting During Ef-G-Catalyzed Translocation., Gabriel Demo, Howard Gamper, Anna B. Loveland, Isao Masuda, Christine E. Carbone, Egor Svidritskiy, Ya-Ming Hou, Andrei A. Korostelev
Department of Biochemistry and Molecular Biology Faculty Papers
Frameshifting of mRNA during translation provides a strategy to expand the coding repertoire of cells and viruses. How and where in the elongation cycle +1-frameshifting occurs remains poorly understood. We describe seven ~3.5-Å-resolution cryo-EM structures of 70S ribosome complexes, allowing visualization of elongation and translocation by the GTPase elongation factor G (EF-G). Four structures with a + 1-frameshifting-prone mRNA reveal that frameshifting takes place during translocation of tRNA and mRNA. Prior to EF-G binding, the pre-translocation complex features an in-frame tRNA-mRNA pairing in the A site. In the partially translocated structure with EF-G•GDPCP, the tRNA shifts to the +1-frame near …
Structure Of The Atp Synthase Catalytic Complex (F(1)) From Escherichia Coli In An Autoinhibited Conformation., Gino Cingolani, Thomas M Duncan
Structure Of The Atp Synthase Catalytic Complex (F(1)) From Escherichia Coli In An Autoinhibited Conformation., Gino Cingolani, Thomas M Duncan
Department of Biochemistry and Molecular Biology Faculty Papers
ATP synthase is a membrane-bound rotary motor enzyme that is critical for cellular energy metabolism in all kingdoms of life. Despite conservation of its basic structure and function, autoinhibition by one of its rotary stalk subunits occurs in bacteria and chloroplasts but not in mitochondria. The crystal structure of the ATP synthase catalytic complex (F(1)) from Escherichia coli described here reveals the structural basis for this inhibition. The C-terminal domain of subunit ɛ adopts a heretofore unknown, highly extended conformation that inserts deeply into the central cavity of the enzyme and engages both rotor and stator subunits in extensive contacts …
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 …
Asymmetric Deactivation Of Hiv-1 Gp41 Following Fusion Inhibitor Binding., Kristen M Kahle, H Kirby Steger, Michael J Root
Asymmetric Deactivation Of Hiv-1 Gp41 Following Fusion Inhibitor Binding., Kristen M Kahle, H Kirby Steger, Michael J Root
Department of Biochemistry and Molecular Biology Faculty Papers
Both equilibrium and nonequilibrium factors influence the efficacy of pharmaceutical agents that target intermediate states of biochemical reactions. We explored the intermediate state inhibition of gp41, part of the HIV-1 envelope glycoprotein complex (Env) that promotes viral entry through membrane fusion. This process involves a series of gp41 conformational changes coordinated by Env interactions with cellular CD4 and a chemokine receptor. In a kinetic window between CD4 binding and membrane fusion, the N- and C-terminal regions of the gp41 ectodomain become transiently susceptible to inhibitors that disrupt Env structural transitions. In this study, we sought to identify kinetic parameters that …
Characterization Of Hard2, A Processed Hard1 Gene Duplicate, Encoding A Human Protein N-Alpha-Acetyltransferase., Thomas Arnesen, Matthew J Betts, Frédéric Pendino, David A Liberles, Dave Anderson, Jaime Caro, Xianguo Kong, Jan E Varhaug, Johan R Lillehaug
Characterization Of Hard2, A Processed Hard1 Gene Duplicate, Encoding A Human Protein N-Alpha-Acetyltransferase., Thomas Arnesen, Matthew J Betts, Frédéric Pendino, David A Liberles, Dave Anderson, Jaime Caro, Xianguo Kong, Jan E Varhaug, Johan R Lillehaug
Department of Medicine Faculty Papers
BACKGROUND: Protein acetylation is increasingly recognized as an important mechanism regulating a variety of cellular functions. Several human protein acetyltransferases have been characterized, most of them catalyzing epsilon-acetylation of histones and transcription factors. We recently described the human protein acetyltransferase hARD1 (human Arrest Defective 1). hARD1 interacts with NATH (N-Acetyl Transferase Human) forming a complex expressing protein N-terminal alpha-acetylation activity. RESULTS: We here describe a human protein, hARD2, with 81 % sequence identity to hARD1. The gene encoding hARD2 most likely originates from a eutherian mammal specific retrotransposition event. hARD2 mRNA and protein are expressed in several human cell lines. …