UC San Diego
Fibrinogen binding mediated by various serotypes of the streptococcal M protein
- Author(s): Latif, Hannah
- et al.
Group A Streptococcus is a human pathogen responsible for causing a variety of diseases that range in severity, from common infections such as strep throat and impetigo, to the more severe necrotizing fasciitis and streptococcal toxic shock syndrome. Streptococcal M protein is a virulence factor which the pathogen presents on its surface to aid in both evasion of host engulfment and disease progression. M proteins are able to interact with human plasma proteins, such as fibrinogen, to accomplish disease progression and thus, further study of the M protein is necessary for understanding virulence mechanisms employed by Streptococcus and for development of preventive medicine. This study surveys fibrinogen- binding as mediated by M proteins of disease implicated Streptococcus pyogenes. Through the use of cloning and protein purification methods, various serotypes of the antigenically variable M protein were prepared for a binding assay with fibrinogen. Whereas several M proteins, such as M1 and M5, are known to bind fibrinogen, it is unknown whether the M3, M6, M22, and M28 serotypes are able to do so. My results show that while M1, M3, M5, M6, and M28 were able to bind, M22 was not. The information indicates not all M proteins possess ability to aid in disease progression by binding fibrinogen. It was also revealed that M proteins bind different regions of the fibrinogen molecule