Oxidation of translation factor EF-G transiently retards the translational elongation cycle in Escherichia coli.
In Escherichia coli, elongation factor G (EF-G), a key protein in translational elongation, is particularly susceptible to oxidation. We demonstrated previously that EF-G is inactivated upon formation of an intramolecular disulphide bond. However, the details of the mechanism by which the oxidation of EF-G inhibits the function of EF-G on the ribosome remain to be elucidated. When we oxidized EF-G with hydrogen peroxide, neither the insertion of EF-G into the ribosome nor single-cycle translocation activity in vitro was affected. However, the GTPase activity and the dissociation of EF-G from the ribosome were suppressed when EF-G was oxidized. The synthesis of longer peptides was suppressed to a greater extent than that of a shorter peptide when EF-G was oxidized. Thus, the formation of the disulphide bond in EF-G might interfere with the hydrolysis of GTP that is coupled with dissociation of EF-G from the ribosome and might thereby retard the turnover of EF-G within the translational machinery. When we added thioredoxin to the suppressed translation system that included oxidized EF-G, translational activity was almost immediately restored. We propose that oxidation of EF-G might provide a regulatory mechanism for transient and reversible suppression of translation in E. coli under oxidative stress.
Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University;
Takanori
T
Nagano
Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University;
Rayakorn
R
Yutthanasirikul
Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University; Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan;
Yukako
Y
Hihara
Chemical Resources Laboratory, Tokyo Institute of Technology, 4259 Nagatsuta, Yokohama 226-8503;
Toru
T
Hisabori
GeneFrontier Corporation, 5-4-19 Kashiwanoha, Kashiwa 277-0882; and Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8562, Japan.
Takashi
T
Kanamori
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8562, Japan.
Nono
N
Takeuchi
Department of Medical Genome Sciences, Graduate School of Frontier Sciences, University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa 277-8562, Japan.
Takuya
T
Ueda
Department of Biochemistry and Molecular Biology, Graduate School of Science and Engineering, Saitama University; Institute for Environmental Science and Technology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan; nishiyama@molbiol.saitama-u.ac.jp.
Yoshitaka
Y
Nishiyama
D004926:Escherichia coli / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000494:pharmacology; D006868:Hydrolysis / Q000187:drug effects; D050505:Mutant Proteins / Q000378:metabolism; D010084:Oxidation-Reduction; D010441:Peptide Chain Elongation, Translational; D020653:Peptide Elongation Factor G / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D012343:RNA, Transfer / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D013879:Thioredoxins / Q000378:metabolism
D050505:Mutant Proteins; D020653:Peptide Elongation Factor G; D010455:Peptides; D013879:Thioredoxins; D006160:Guanosine Triphosphate; D012343:RNA, Transfer; D006861:Hydrogen Peroxide
EF-G; GTP hydrolysis; oxidative stress; protein synthesis; redox regulation