Mutant ribosomes can generate dominant kirromycin resistance
1991 (English)In: Journal of Bacteriology, ISSN 0021-9193, E-ISSN 1098-5530, Vol. 173, no 12, 3635-3643 p.Article in journal (Refereed) Published
Mutations in the two genes for EF-Tu in Salmonella typhimuriumand Escherichia coli, tufA and tufB, can confer resistance tothe antibiotic kirromycin. Kirromycin resistance is a recessivephenotype expressed when both tuf genes are mutant. We describea new kirromycin-resistant phenotype dominant to the effectof wild-type EF-Tu. Strains carrying a single kirromycin-resistanttuf mutation and an error-restrictive, streptomycin-resistantrpsL mutation are resistant to high levels of kirromycin, evenwhen the other tuf gene is wild type. This phenotype is dependenton error-restrictive mutations and is not expressed with nonrestrictivestreptomycin-resistant mutations. Kirromycin resistance is alsoexpressed at a low level in the absence of any mutant EF-Tu.These novel phenotypes exist as a result of differences in theinteractions of mutant and wild-type EF-Tu with the mutant ribosomes.The restrictive ribosomes have a relatively poor interactionwith wild-type EF-Tu and are thus more easily saturated withmutant kirromycin-resistant EF-Tu. In addition, the mutant ribosomesare inherently kirromycin resistant and support a significantlyfaster EF-Tu cycle time in the presence of the antibiotic thando wild-type ribosomes. A second phenotype associated with combinationsof rpsL and error-prone tuf mutations is a reduction in thelevel of resistance to streptomycin.
Place, publisher, year, edition, pages
1991. Vol. 173, no 12, 3635-3643 p.
Microbiology in the medical area
IdentifiersURN: urn:nbn:se:uu:diva-47264OAI: oai:DiVA.org:uu-47264DiVA: diva2:75171