The secY gene of V. cholerae: identification, cloning and characterization.
The secY gene of Vibrio cholerae has been cloned and the complete nt sequence determined. It codes for a protein of 438 aa residues which functions as a translocator through which proteins cross the inner membrane. It can substitute for the Escherichia coli SecY protein and can suppress the phenotypic traits associated with E. coli secY mutants. The V. cholerae secY gene has about 71 and 83% similarity at the nt and aa levels respectively with the E. coli secY gene. Vibrio cholerae secY, similarly to the E. coli secY, is flanked by the genes encoding the ribosomal large subunit proteins L15 and L36. When expressed from the lac promoter, V. cholerae secY partially complements E. coli secY mutation even in absence of IPTG, while the E. coli secY gene complements only when IPTG is present. Presence of multiple SD sequences and a putative downstream (DS) box imply that the V. cholerae secY gene might have high translational efficiency. A V. cholerae mutant unable to translocate CTB through the inner membrane has been isolated. The secretion deficient phenotype of the mutant can be reversed by introducing the cloned V. cholerae secY gene.
Bhattacharyya
D
D
Biophysics Division, Indian Institute of Chemical Biology, Calcutta, India.
Das
J
J
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001483:Base Sequence; D001692:Biological Transport; D002462:Cell Membrane / Q000378:metabolism; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005816:Genetic Complementation Test; D008969:Molecular Sequence Data; D009154:Mutation; D000069816:SEC Translocation Channels; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014734:Vibrio cholerae / Q000235:genetics*
D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D000069816:SEC Translocation Channels; C057841:SecY protein, E coli