Chemical probing of a virginiamycin M-promoted conformational change of the peptidyl-transferase domain.
Previous findings suggest the location of the central loop of domain V of 23S rRNA within the peptidyltransferase domain of ribosomes. This enzymatic activity is inhibited by some antibiotics, including type A (virginiamycin M or VM) and type B (virginiamycin S or VS) synergimycins, antibiotics endowed with a synergistic action in vivo. In the present work, the ability of VM and VS to modify the accessibility of 23S rRNA bases within ribosomes to chemical reagents has been explored. VM afforded a protection of rRNA bases A2037, A2042, G2049 and C2050. Moreover, when ribosomes were incubated with the two virginiamycin components, the base A2062, which was protected by VS alone, became accessible to dimethyl sulphate (DMS). Modified reactivity to chemical reagents of different rRNA bases located either in the central loop of domain V or in its proximity furnishes experimental evidence for conformational ribosome alterations induced by VM binding.
Microbiology and Genetics Unit, University of Louvain, Medical School, Brussels, Belgium.
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Vannuffel
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Di Giambattista
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D000447:Aldehydes / Q000494:pharmacology; D001483:Base Sequence; D002074:Butanones; D004047:Diethyl Pyrocarbonate / Q000494:pharmacology; D004357:Drug Synergism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010458:Peptidyl Transferases / Q000037:antagonists & inhibitors / Q000737:chemistry*; D011487:Protein Conformation / Q000187:drug effects; D012338:RNA, Ribosomal, 23S / Q000737:chemistry* / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism; D013463:Sulfuric Acid Esters / Q000494:pharmacology; D014769:Virginiamycin / Q000378:metabolism / Q000494:pharmacology*
D000447:Aldehydes; D002074:Butanones; D012338:RNA, Ribosomal, 23S; D013463:Sulfuric Acid Esters; D014769:Virginiamycin; C005135:kethoxal; D010458:Peptidyl Transferases; C007482:dimethyl sulfate; D004047:Diethyl Pyrocarbonate