The Carboxyl-Terminal Amino Acid Sequence of Streptomyces griseus Protease A

The sequence of 62 amino acid residues from the COOH-terminus of Streptomyces griseus Protease A has been established from peptic peptides previously described and from α-lytic protease and tryptic digests of the aminoethylated cyanogen bromide COOH-terminal fragment of the protein. This sequence includes one of the two disulfide bridges of the protein and the characteristic Asp–Ser–Gly sequence of this class of protease. When comparisons of residue similarity are made, the Streptomyces griseus Protease A sequence appears to be more similar (53% extent of similarity) to that of Myxobacter α-lytic protease than to any other protease. Both proteins appear to have common insertions at residue positions 189 and 192, and have characteristic clusters of hydrophobic residues near the COOH-terminus which are also present in other Asp–Ser–Gly proteases.