The mechanism of error induction by the antibiotic viomycin provides insight into the fidelity mechanism of translation

• Published in: eLife Vol. 8
• Main Authors: Holm, Mikael, Mandava, Chandra Sekhar, Ehrenberg, Måns, Sanyal, Suparna
• Format: Journal Article
• Language: English
• Published: England eLife Sciences Publications Ltd 07.06.2019; eLife Sciences Publications, Ltd
• Subjects: Accuracy; Acids; Anti-Bacterial Agents - pharmacology; antibiotic; Antibiotics; Bacterial proteins; Binding sites; Biochemistry and Chemical Biology; Cell-Free System; Conformation; E coli; Elongation factor EF-Tu; Enzyme kinetics; Genetic code; Guanosine triphosphate; Peptides; Proofreading; Protein Biosynthesis - drug effects; Protein synthesis; Protein Synthesis Inhibitors - pharmacology; ribosome; Ribosomes; Translation; tRNA; Viomycin; Viomycin - pharmacology; United States > US; antibiotic; chemical biology; biochemistry; translation; protein synthesis; ribosome; viomycin; E. coli
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/eLife.46124

Applying pre-steady state kinetics to an based reconstituted translation system, we have studied how the antibiotic viomycin affects the accuracy of genetic code reading. We find that viomycin binds to translating ribosomes associated with a ternary complex (TC) consisting of elongation factor Tu (EF-Tu), aminoacyl tRNA and GTP, and locks the otherwise dynamically flipping monitoring bases A1492 and A1493 into their active conformation. This effectively prevents dissociation of near- and non-cognate TCs from the ribosome, thereby enhancing errors in initial selection. Moreover, viomycin shuts down proofreading-based error correction. Our results imply a mechanism in which the accuracy of initial selection is achieved by larger backward rate constants toward TC dissociation rather than by a smaller rate constant for GTP hydrolysis for near- and non-cognate TCs. Additionally, our results demonstrate that translocation inhibition, rather than error induction, is the major cause of cell growth inhibition by viomycin.