ISSN:
1617-4623
Keywords:
Key words Silent mutation
;
FtsH protein
;
Translation initiation
;
Colicin tolerance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Among Escherichia coli tolZ mutants tolerant to colicins E2, E3, and D, one, KHI10, had a high frequency of λ lysogenization, like the tolZ21 mutant, but unlike tolZ21 KHI10 grew on nonfermentable carbon sources. The tolZ10 gene of KHI10 was cloned and sequenced, and found to have a silent mutation in the ftsH gene, causing an alteration of a minor codon, CUA, for Leu-5 to a suboptimal codon, CUC. In spite of the change in a minor codon, the amount of the FtsH protein present in mutant cells was much less than that in the parental strain. In vivo transcription of the tolZ10 gene was not decreased relative to the wild-type ftsH gene. Analysis of other silent mutations altering the Leu-5 codon (CUA) to CUG or CUU (optimal and suboptimal codons, respectively) revealed that the decrease in concentration of FtsH was seen only with the CUC (tolZ10) codon. Prediction of the mRNA secondary structure suggested that the change from A to C extends the base pairing region longer by one base pair at the root of the stem structure, thus sequestering the Shine-Dalgarno sequence and decreasing the rate of the translational initiation of FtsH.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s004380050454
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