title: Maturation processing and characterization of streptopain.
abstract: Streptopain is a cysteine protease expressed by Streptococcus pyogenes. To study the maturation mechanism of streptopain, wild-type and Q186N, C192S, H340R, N356D and W357A mutant proteins were expressed in Escherichia coli and purified to homogeneity. Proteolytic analyses showed that the maturation of prostreptococcal pyrogenic exotoxin B zymogen (pro-SPE B) involves eight intermediates with a combination of cis- and trans-processing. Based on the sequences of these intermediates, the substrate specificity of streptopain favors a hydrophobic residue at the P2 site. The relative autocatalytic rates of these mutants exhibited the order Q186N > W357A > N356D, C192S, H340R. Interestingly, the N356D mutant containing protease activity could not be converted into the 28-kDa form by autoprocessing. This observation suggested that Asn(356) might involve the cis-processing of the propeptide. In addition, the maturation rates of pro-SPE B with trypsin and plasmin were 10- and 60-fold slower than that with active mature streptopain. These findings indicate that active mature streptopain likely plays the most important role in the maturation of pro-SPE B under physiological conditions.
authors.affiliation: Department of Biochemistry, National Cheng Kung University College of Medicine, 1 University Road, Tainan 701, Taiwan.
authors.forename: Chiu-Yueh
authors.initials: CY
authors.lastname: Chen
authors.forename: Shih-Chi
authors.initials: SC
authors.lastname: Luo
authors.forename: Chih-Feng
authors.initials: CF
authors.lastname: Kuo
authors.forename: Yee-Shin
authors.initials: YS
authors.lastname: Lin
authors.forename: Jiunn-Jong
authors.initials: JJ
authors.lastname: Wu
authors.forename: Ming T
authors.initials: MT
authors.lastname: Lin
authors.forename: Ching-Chuan
authors.initials: CC
authors.lastname: Liu
authors.forename: Wen-Yih
authors.initials: WY
authors.lastname: Jeng
authors.forename: Woei-Jer
authors.initials: WJ
authors.lastname: Chuang
mesh_terms: D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004926:Escherichia coli; D005341:Fibrinolysin; D008969:Molecular Sequence Data; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism; D013297:Streptococcus pyogenes / Q000201:enzymology*; D014357:Trypsin
chemical_list: D011994:Recombinant Proteins; D014357:Trypsin; D005341:Fibrinolysin; D003546:Cysteine Endopeptidases; C042477:streptopain