Logo image
Genomic location and variation of the gene for CRS, a complement binding protein in the M57 strains of Streptococcus pyogenes
Journal article   Open access   Peer reviewed

Genomic location and variation of the gene for CRS, a complement binding protein in the M57 strains of Streptococcus pyogenes

M Binks, David J McMillan and K S Sriprakash
Infection and immunity, Vol.71(12), pp.6701-6706
2003
pdf
PDF - Published Version603.77 kBDownloadView
Published VersionPDF - Published Version Open Access
url
https://doi.org/10.1128/iai.71.12.6701-6706.2003View
Published Version

Abstract

Biological Sciences Medical and Health Sciences Agricultural and Veterinary Sciences
All isolates of serotype M1 of group A streptococci possess a gene for streptococcal inhibitor of complement (SIC) in the mga regulon, which harbors genes for other virulence factors, such as M and M-like proteins, C5a peptidase, and a regulator. In serotype M57 the gene for a protein that is closely related to SIC (crs57) is located outside the mga regulon. We mapped the location of the crs57 gene in six strains of emm57 (gene encoding the M57 protein) sequence types to an intergenic region between the ABC transporter gene (SPy0778) and the gene for a small ribosomal protein (rpsU). The noncoding sequences on both sides of crs57 exhibited high degrees of identity to the corresponding regions of sic from M1 strains. This included one of the inverted repeat sequences of IS1562 but not the insertion element itself. These observations suggest that crs57 was recently acquired by serotype M57 or its progenitor via horizontal acquisition from serotype M1. The six emm57 sequence type isolates analyzed in this study belong to two distinct molecular types (vir types VT8 and VT101). Although the crs57 sequences from VT8 strains had very few substitution mutations, the VT101 crs57 sequence had a large number of such mutations. The CRS57 proteins from these strains are secretory products and have the ability to bind to complement proteins. All these proteins contain several tryptophan-rich repeats designated DWS motifs and internal repeat sequences. In all of these structural and biochemical characteristics CRS57 resembles SIC from M1 strains. Hence, CRS57 has a functional role similar to that of SIC in an M1 strain.

Details

Metrics

30 File views/ downloads
597 Record Views
Logo image