Published by Elsevier FEMSLE ~1~ Limited repertoire of the C-terminal region of the M protein in Streptococcus pyogenes

We have amplified genomic sequences (emm) that may encode M protein from strains of Streptococcus pyogenes using the polymerase chain reaction (PER). Genomic DNA from 22 isolates representing 14 M scretypes was selected for the study. Primers which corresponded to the ob-served N-terminal signal sequence and the varia-ble C-terminal sequences of emm6, emm49 and ennX were used. PCR products using emm6 and emm49 oligonucleotides were classified into two mutually exclusive groups which corresponded to the presence or absence of serum opacity factor. These findings support the concept of limited het-erogeneity in the C-terminal sequences of the M protein. 2