The gene encoding the prepilin peptidase involved in biosynthesis of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli. |
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Authors: | T Taniguchi Y Yasuda K Tochikubo K Yamamoto T Honda |
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Institution: | Department of Microbiology, Nagoya City University Medical School, Nagoya, Aichi, Japan. |
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Abstract: | The assembly of pilus colonization factor antigen III (CFA/III) of human enterotoxigenic Escherichia coli requires the processing of CFA/III major pilin (CofA) by a peptidase, likely another type IV pilus formation system. Western 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 the CofA from the cytoplasm to the periplasm. In this experiment, the structural 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 acid 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 amino acid sequence of CofP shows a high degree of homology with other prepilin peptidases which play a role in the assembly of type IV pili in several gram-negative bacteria. |
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Keywords: | ETEC CFA/III prepilin peptidase nucleotide sequence |
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