title: Streptomyces griseus protease C. A novel enzyme of the chymotrypsin superfamily.
abstract: In this report we describe a novel chymotrypsin-like serine protease produced by Streptomyces griseus. The enzyme has been tentatively named S. griseus protease C (SGPC). The gene encoding the enzyme (sprC) was identified and isolated on the basis of its homology to the previously characterized S. griseus protease B (SGPB). The sprC gene encodes a 457-amino acid prepro-mature protein of which only the 255 carboxyl-terminal amino acids are present in the mature enzyme. Mature SGPC contains two distinct domains connected by a 19-amino acid linker region rich in threonines and prolines. While the amino-terminal domain is homologous to S. griseus proteases A, B, and E and the alpha-lytic protease of Lysobacter enzymogenes, the carboxyl-terminal domain is not homologous with any known protease. However, the carboxyl-terminal domain shares extensive homology with chitin-binding domains of Bacillus circulans chitinases A1 and D, suggesting that the enzyme is specialized for the degradation of chitin-linked proteins. Recombinant expression and preliminary characterization of the catalytic properties of the enzyme are also reported. The primary specificity of SGPC is similar to that of SGPB; both enzymes preferentially cleave peptide bonds following large hydrophobic side chains.
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: S S
authors.initials: SS
authors.lastname: Sidhu
authors.forename: G B
authors.initials: GB
authors.lastname: Kalmar
authors.forename: L G
authors.initials: LG
authors.lastname: Willis
authors.forename: T J
authors.initials: TJ
authors.lastname: Borgford
mesh_terms: D000595:Amino Acid Sequence; D001412:Bacillus subtilis / Q000235:genetics; D001483:Base Sequence; D015139:Blotting, Southern; D002852:Chromatography, Ion Exchange; D002918:Chymotrypsin / Q000235:genetics*; D003001:Cloning, Molecular; D004269:DNA, Bacterial; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D013305:Streptomyces griseus / Q000201:enzymology*
chemical_list: D004269:DNA, Bacterial; D012697:Serine Endopeptidases; C088701:protease C; D002918:Chymotrypsin