Characterization of the gene rimK responsible for the addition of glutamic acid residues to the C-terminus of ribosomal protein S6 in Escherichia coli K12.
Ribosomal protein S6 of wild-type strains of Escherichia coli contains up to six glutamic acid residues at its C-terminus. The first two residues are encoded by the structural gene for this protein (rpsF) and the rest are added post-translationally. Mutants deficient in this modification were isolated and characterized genetically and biochemically. The S6 protein in these mutants appeared to contain only two glutamic acid residues at the C-terminus as expected. The mutated gene was termed rimK and was mapped at 18.7 min between cmlA and aroA. The rimK gene was cloned into a cosmid vector and its nucleotide sequence determined. Analysis of the transcriptional and translational products of this gene indicates that it encodes a protein with an Mr of 31.5 kDa and that it forms an operon with a gene encoding a 24 kDa protein. An rpsF mutant containing a Glu to Lys replacement in the second residue from the C-terminus of protein S6 was isolated. The S6 protein of this mutant was apparently inaccessible to the RimK modification system. This indicates that the RimK modification system requires the wild-type amino acid sequence at least in the C-terminal region of ribosomal protein S6.
Kang
W K
WK
Department of Biology, Faculty of Science, Kobe University, Japan.
Icho
T
T
Isono
S
S
Kitakawa
M
M
Isono
K
K
D000595:Amino Acid Sequence; D001483:Base Sequence; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D005798:Genes, Bacterial; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins / Q000235:genetics* / Q000378:metabolism; D014158:Transcription, Genetic
D004269:DNA, Bacterial; D005971:Glutamates; D038601:Ribosomal Protein S6; D012269:Ribosomal Proteins; D018698:Glutamic Acid