Limited repertoire of the C-terminal region of the M protein in Streptococcus pyogenes

Abstract

We have amplified genomic sequences (emm) that may encode M protein from strains of Streptococcus pyogenes using the polymerase chain reaction (PCR). Genomic DNA from 22 isolates representing 14 M serotypes was selected for the study. Primers which corresponded to the observed N-terminal signal sequence and the variable 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 correspond to the presence or absence of serum opacity factor. These findings support the concept of limited heterogeneity in the C-terminal sequences of the M protein.

Molecular epidemiological investigation of an outbreak of invasive β-haemolytic streptococcal infection in western Norway

“…As the C‐terminal end is conserved among many types, it came as no surprise that this region showed a high degree of homology to many different emm types. This region, however, is known to differ between the opacity factor‐producing (OF + ) and opacity factor‐non‐producing (OF − ) types [45]. Consistent with this, the homology observed in the study isolates was generally confined to the types within either the OF + group or OF − group.…”

Group A Streptococcal Vir Types Are M-Protein Gene (emm) Sequence Type Specific

“…emm sequence analysis. The template DNA used to determine the hypervariable region of emm was either the PCR product from Vir typing as described above or an emm-specific amplification product (18,28). PCR primers were removed by isopropanol precipitation before cycle sequencing with pF (28).…”

“…The template DNA used to determine the hypervariable region of emm was either the PCR product from Vir typing as described above or an emm-specific amplification product (18,28). PCR primers were removed by isopropanol precipitation before cycle sequencing with pF (28). To ensure that there was no sampling bias, the isolates of each VT used for sequencing were chosen, whenever possible, from different communities at different time points over the period of the study.…”

Identification of sequence types among the M-nontypeable group A streptococci

“…Antisera to the following M proteins were used: 1, 3, 3R, 5,6,12,14,18,24,26,29,41,52, 53, 55, 57, and 80. OF antisera for types 2,4,13,22,25,28,49,58,59,60,61,63,66,68,73,75,77,81, PT180, NZ1437, PT1658, Tr2407, Tr2612, PT2841, PT3875, and NZ5118 were used for OF-positive organisms.…”