The secG deletion mutation of Escherichia coli is suppressed by expression of a novel regulatory gene of Bacillus subtilis.
SecG, a membrane component of E. coli protein translocase, stimulates the translocation of proteins across the cell membrane through the cycle of topology inversion, which is coupled to the membrane-insertion and deinsertion cycle of SecA [Nishiyama et al. (1996) Cell 85, 71-81]. A gene of B. subtilis able to suppress the cold-sensitive phenotype of the secG deletion mutant of E. coli was cloned and found to encode a novel regulatory protein, ScgR. Similarity search revealed homology with known proteins such as GlnR of B. subtilis. Plasmid-encoded ScgR stimulated protein translocation in the deletion mutant. ScgR increased the proportion of cardiolipin at the expense of phosphatidylglycerol, but did not affect the composition of other lipid components of the cell, suggesting that the increased cardiolipin level compensates for the SecG function and thereby stimulates protein translocation.
Kontinen
V P
VP
Laboratory of Vaccine Development, National Public Health Institute, Helsinki, Finland.
Helander
I M
IM
Tokuda
H
H
D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D001483:Base Sequence; D001692:Biological Transport; D002455:Cell Division; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins; D004926:Escherichia coli / Q000737:chemistry / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins; D017353:Gene Deletion; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D008969:Molecular Sequence Data; D010743:Phospholipids / Q000032:analysis; D012097:Repressor Proteins; D015183:Restriction Mapping; D000069816:SEC Translocation Channels; D017385:Sequence Homology; D013489:Suppression, Genetic; D015534:Trans-Activators / Q000737:chemistry / Q000235:genetics; D014157:Transcription Factors
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C082451:GlnR protein, Streptomyces coelicolor; D008565:Membrane Proteins; D010743:Phospholipids; D012097:Repressor Proteins; D000069816:SEC Translocation Channels; C101458:ScgR protein, Bacillus subtilis; C088616:SecG protein, E coli; D015534:Trans-Activators; D014157:Transcription Factors