Viomycin does not stimulate the dissociation of peptidyl-tRNA.
Peptidyl-transfer RNA normally dissociates at a low rate from the ribosomes of Escherichia coli during protein synthesis but accumulates under nonpermissive conditions in cells with a temperature-sensitive allele (pthts) of the gene encoding peptidyl-transfer RNA hydrolase. The antibiotic-hypersensitive strain E. coli DB-11 with the pthts mutation was exposed to viomycin, then placed at nonpermissive temperatures. Under these conditions in the absence of drugs, peptidyl-tRNA accumulates, protein synthesis is inhibited and pthts cells die. When viomycin was present at sufficient concentration to arrest protein synthesis, cell death was not accelerated, error-inducing effects of streptomycin were not counteracted and, at high doses, cytoplasmic accumulation of peptidyl-transfer RNA was slowed down. Blocking the translocation of peptidyl-transfer RNA with viomycin did not stimulate its dissociation from ribosomes. Erythromycin-enhanced cell death was not affected by viomycin at doses sufficient to block amino acid incorporation, suggesting that short peptidyl-transfer RNAs could still be synthesized and dissociated from ribosomes.
Menninger
J R
JR
Department of Biological Sciences, University of Iowa, Iowa City 52242-1324, USA.
D004338:Drug Combinations; D004917:Erythromycin / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D012343:RNA, Transfer / Q000096:biosynthesis / Q000187:drug effects*; D012346:RNA, Transfer, Amino Acyl / Q000096:biosynthesis / Q000187:drug effects*; D014756:Viomycin / Q000494:pharmacology*
D004338:Drug Combinations; D012346:RNA, Transfer, Amino Acyl; C019037:tRNA, peptidyl-; D004917:Erythromycin; D012343:RNA, Transfer; D014756:Viomycin