A silent mutation in the ftsH gene of Escherichia coli that affects FtsH protein production and colicin tolerance.
Among Escherichia coli tolZ mutants tolerant to colicins E2, E3, and D, one, KHI10, had a high frequency of lambda 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.
Makino
S
S
Department of Biotechnology, The University of Tokyo, Bunkyo-ku, Japan.
Qu
J N
JN
Uemori
K
K
Ichikawa
H
H
Ogura
T
T
Matsuzawa
H
H
D049069:ATP-Dependent Proteases; D000469:Alkaline Phosphatase / Q000096:biosynthesis / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001483:Base Sequence; D003062:Codon / Q000235:genetics; D003087:Colicins / Q000494:pharmacology*; D004252:DNA Mutational Analysis; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial / Q000235:genetics*; D007930:Leucine / Q000235:genetics; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D009355:Neomycin / Q000494:pharmacology; D009690:Nucleic Acid Conformation; D010641:Phenotype; D017354:Point Mutation / Q000235:genetics*; D012329:RNA, Bacterial / Q000032:analysis / Q000737:chemistry; D012333:RNA, Messenger / Q000032:analysis / Q000737:chemistry; D011993:Recombinant Fusion Proteins
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D003062:Codon; D003087:Colicins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D000469:Alkaline Phosphatase; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli; D007930:Leucine; D009355:Neomycin