title: Different forms of streptolysin O produced by Streptococcus pyogenes and by Escherichia coli expressing recombinant toxin: cleavage by streptococcal cysteine protease.
abstract: To resolve apparent discrepancies in the literature, N-terminal sequences of the active high- and low-molecular-weight (high- and low-M(r)) forms of native streptolysin O (nSLO) purified from Streptococcus pyogenes culture supernatants and of the similar-size high- and low-M(r) forms of recombinant SLO (rSLO) found in the periplasm of Escherichia coli expressing a cloned slo gene were determined. The high-M(r) forms of nSLO and rSLO are identical, reflecting removal of a 31-residue signal peptide, but the similar-size low-M(r) forms are very different. Removal of C-terminal sequences by proteases in the E. coli periplasm produces an inactive low-M(r) form of rSLO. In contrast, an active low-M(r) form of nSLO is produced by proteolytic cleavage between the N-terminal residues Lys-77 and Leu-78, which was shown to correspond to an extremely sensitive cleavage site for the pyrogenic exotoxin B-derived streptococcal cysteine protease.
authors.affiliation: Department of Microbiology, Medical School, University of Newcastle, Newcastle upon Tyne, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Pinkney
authors.forename: V
authors.initials: V
authors.lastname: Kapur
authors.forename: J
authors.initials: J
authors.lastname: Smith
authors.forename: U
authors.initials: U
authors.lastname: Weller
authors.forename: M
authors.initials: M
authors.lastname: Palmer
authors.forename: M
authors.initials: M
authors.lastname: Glanville
authors.forename: M
authors.initials: M
authors.lastname: Messner
authors.forename: J M
authors.initials: JM
authors.lastname: Musser
authors.forename: S
authors.initials: S
authors.lastname: Bhakdi
authors.forename: M A
authors.initials: MA
authors.lastname: Kehoe
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins; D003546:Cysteine Endopeptidases / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping; D011994:Recombinant Proteins / Q000737:chemistry*; D013297:Streptococcus pyogenes / Q000378:metabolism*; D013301:Streptolysins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D013301:Streptolysins; C025964:streptolysin O; D003546:Cysteine Endopeptidases