Different forms of streptolysin O produced by Streptococcus pyogenes and by Escherichia coli expressing recombinant toxin: cleavage by streptococcal cysteine protease.
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.
Pinkney
M
M
Department of Microbiology, Medical School, University of Newcastle, Newcastle upon Tyne, United Kingdom.
Kapur
V
V
Smith
J
J
Weller
U
U
Palmer
M
M
Glanville
M
M
Messner
M
M
Musser
J M
JM
Bhakdi
S
S
Kehoe
M A
MA
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
D001426:Bacterial Proteins; D011994:Recombinant Proteins; D013301:Streptolysins; C025964:streptolysin O; D003546:Cysteine Endopeptidases