Different forms of streptolysin O produced by Streptococcus pyogenes and by Escherichia coli expressing recombinant toxin: cleavage by streptococcal cysteine protease

Infect Immun. 1995 Jul;63(7):2776-9. doi: 10.1128/iai.63.7.2776-2779.1995.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins
  • Cysteine Endopeptidases / metabolism
  • Escherichia coli / metabolism*
  • Molecular Sequence Data
  • Molecular Weight
  • Peptide Mapping
  • Recombinant Proteins / chemistry*
  • Streptococcus pyogenes / metabolism*
  • Streptolysins / chemistry*
  • Streptolysins / metabolism

Substances

  • Bacterial Proteins
  • Recombinant Proteins
  • Streptolysins
  • streptolysin O
  • Cysteine Endopeptidases