M-LIKE, IMMUNOGLOBULIN-BINDING PROTEIN OF STREPTOCOCCUS-PYOGENES TYPEM15

An M-like protein from Streptococcus pyogenes type M15 strain EF1949 ( EMML15) was cloned in Escherichia coli and sequenced. Recombinant EMML 15 protein revealed a unique binding pattern for human IgG subclasses not described previously. Comparative analysis of the EMML15 amino aci d sequence with those of other M-like proteins of opacity factor posit ive (OF+) serotypes and protein H, an IgG receptor from OF- serotype M 1, showed that IgG-binding proteins with common binding of IgG3 were c losely related and distinct from streptococcal IgG receptors not bindi ng IgG3. Thus, the Ig-binding proteins from S. pyogenes were subdivide d into two main categories according to binding pattern, protein struc ture, and gene location.