Format:
Online-Ressource
ISSN:
1460-2075
Content:
In bacteria, SsrA RNA recognizes ribosomes stalled on defective messages and acts as a tRNA and mRNA to mediate the addition of a short peptide tag to the C‐terminus of the partially synthesized nascent polypeptide chain. The SsrA‐tagged protein is then degraded by C‐terminal‐specific proteases. SmpB, a unique RNA‐binding protein that is conserved throughout the bacterial kingdom, is shown here to be an essential component of the SsrA quality‐control system. Deletion of the smpB gene in Escherichia coli results in the same phenotypes observed in ssrA‐defective cells, including a variety of phage development defects and the failure to tag proteins translated from defective mRNAs. Purified SmpB binds specifically and with high affinity to SsrA RNA and is required for stable association of SsrA with ribosomes in vivo. Formation of an SmpB–SsrA complex appears to be critical in mediating SsrA activity after aminoacylation with alanine but prior to the transpeptidation reaction that couples this alanine to the nascent chain. SsrA RNA is present at wild‐type levels in the smpB mutant arguing against a model of SsrA action that involves direct competition for transcription factors.
In:
volume:18
In:
number:13
In:
year:1999
In:
pages:3793-3799
In:
extent:7
In:
European Molecular Biology Organization, The EMBO journal, Heidelberg : EMBO Press, 1982-, 18, Heft 13 (1999), 3793-3799 (gesamt 7), 1460-2075
Language:
English
DOI:
10.1093/emboj/18.13.3793
URN:
urn:nbn:de:101:1-2023112703413001001741
URL:
https://doi.org/10.1093/emboj/18.13.3793
URL:
https://nbn-resolving.org/urn:nbn:de:101:1-2023112703413001001741
URL:
https://d-nb.info/1311244395/34
URL:
https://doi.org/10.1093/emboj/18.13.3793
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