Blasticidin S inhibits translation by trapping deformed tRNA on the ribosome
RNA Therapeutics Institute; Department of Biochemistry and Molecular Pharmacology
Medical Subject Headings
Crystallography, X-Ray; Fluorescence Resonance Energy Transfer; Models, Molecular; Nucleosides; Protein Biosynthesis; RNA, Transfer; Ribosomes; Thermus thermophilus
Biochemistry | Molecular Biology
The antibiotic blasticidin S (BlaS) is a potent inhibitor of protein synthesis in bacteria and eukaryotes. We have determined a 3.4-A crystal structure of BlaS bound to a 70StRNA ribosome complex and performed biochemical and single-molecule FRET experiments to determine the mechanism of action of the antibiotic. We find that BlaS enhances tRNA binding to the P site of the large ribosomal subunit and slows down spontaneous intersubunit rotation in pretranslocation ribosomes. However, the antibiotic has negligible effect on elongation factor G catalyzed translocation of tRNA and mRNA. The crystal structure of the antibiotic-ribosome complex reveals that BlaS impedes protein synthesis through a unique mechanism by bending the 3' terminus of the P-site tRNA toward the A site of the large ribosomal subunit. Biochemical experiments demonstrate that stabilization of the deformed conformation of the P-site tRNA by BlaS strongly inhibits peptidyl-tRNA hydrolysis by release factors and, to a lesser extent, peptide bond formation.
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Citation: Proc Natl Acad Sci U S A. 2013 Jul 23;110(30):12283-8. doi: 10.1073/pnas.1304922110. Epub 2013 Jul 3. Link to article on publisher's site
Svidritskiy, Egor; Ling, Clarence; Ermolenko, Dmitri N.; and Korostelev, Andrei A., "Blasticidin S inhibits translation by trapping deformed tRNA on the ribosome" (2013). University of Massachusetts Medical School Faculty Publications. 474.