The Complete Amino‐Acid Sequence of the K88 Antigen, a Fimbrial Protein from Escherichia coli

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Abstract
The complete primary structure of the fimbrial protein of the K88 antigen has been elucidated. This protein, which makes up the building block for the macromolecular structure that comprises a fimbria, consists of 264 amino acid residues in a single polypeptide chain. The K88 antigen was fragmented by chemical cleavage with cyanogen bromide, and by subsequent enzymatic sub-cleavage of resulting fragments with trypsin and chymotrypsin, and was additionally cleaved with o-iodosobenzoic acid. Peptides were sequenced by manual Edman degradation. The carboxy-terminal part of the molecule is remarkable in being almost devoid of charged amino acid residues and is highly hydrophobic. Furthermore, this part of the structure could have a specific function as a molecular anchor.