Primary Structure of the CFAl Fimbrial Protein from Human Enterotoxigenic Escherichia coli Strains

The complete amino acid sequence of the structural protein that constitutes the subunit of the CFA1 fimbria has been elucidated. The protein was fragmented by cyanogen bromide cleavage, and by enzymatic cleavage with trypsin. Secondary cleavage of the resulting peptides was performed with chymotrypsin, Staphylococcus aureus protease, and thermolysin. Sequential Edman degradation was performed manually. The CFA1 protein comprises 147 amino acid residues, with a molecular weight of 15058.