Molecular cloning and nucleotide sequence of the colonization factor antigen I gene of Escherichia coli

T. K. Karjalainen, D. G. Evans, M. So, C. H. Lee

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The colonization factor antigen I (CFA/I) gene has been isolated and sequenced. The amino acid sequence of CFA/I deduced from the nucleotide sequence is composed of 170 amino acids. The first 23 amino acids are considered to be the signal peptide of the CFA/I protein since they are not present in the protein sequence. Among the remaining amino acids, only 2 are different from the protein sequence: amino acid position 76 is an aspartic acid instead of an asparagine, and position 97 is a serine instead of an alanine. The CFA/I gene has a typical Shine-Dalgarno sequence located 10 base pairs (bp) upstream from the initiation codon. The sequence TACAAT located 48 bp upstream from the initiation codon was tentatively designated the -10 sequence of the CFA/I gene promoter. No sequence homologous to the consensus -35 promoter sequence was found. A pair of inverted repeat sequences followed by a stretch of 8 A's are located 45 bp downstream from the termination codon of the CFA/I gene; this region may be a p-independent transcriptional terminator.

Original languageEnglish (US)
Pages (from-to)1126-1130
Number of pages5
JournalInfection and Immunity
Issue number4
StatePublished - Jan 1 1989


ASJC Scopus subject areas

  • Parasitology
  • Microbiology
  • Immunology
  • Infectious Diseases

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