The gene encoding the prepilin peptidase involved in biosynthesis of piluscolonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli
T. Taniguchi et al., The gene encoding the prepilin peptidase involved in biosynthesis of piluscolonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli, MICROB IMMU, 43(9), 1999, pp. 853-861
The assembly of pilus colonization factor antigen III (CFA/III) of human en
terotoxigenic Escherichia coli requires the processing of CFA/III major pil
in (CofA) by a peptidase, likely another type IV pilus formation system. We
stern blot analysis of CofA reveals that CofA is produced initially as a 26
.5-kDa preform pilin (prepilin) and then processed to 20.5-kDa mature pilin
by a prepilin peptidase. This processing is essential for exportation of t
he CofA from the cytoplasm to the periplasm. In this experiment, the struct
ural gene, cofP, encoding CFA/III prepilin peptidase which cleavages at the
Gly-30-Met-31 junction of CofA was identified, and the nucleotide sequence
of the gene was determined. cofP consists of 819 bp encoding a 273-amino a
cid protein with a relative molecular mass of 30,533 Da. CofP is predicted
to be localized in the inner membrane based on its hydropathy index. The am
ino acid sequence of CofP shows a high degree of homology with other prepil
in peptidases which play a role in the assembly of type IV pill in several
gram-negative bacteria.