Structural highlights
Function
[M21_STRPY] This protein is one of the different antigenic serotypes of protein M. Protein M is closely associated with virulence of the bacterium and can render the organism resistant to phagocytosis. [C4BPA_HUMAN] Controls the classical pathway of complement activation. It binds as a cofactor to C3b/C4b inactivator (C3bINA), which then hydrolyzes the complement fragment C4b. It also accelerates the degradation of the C4bC2a complex (C3 convertase) by dissociating the complement fragment C2a. Alpha chain binds C4b. It interacts also with anticoagulant protein S and with serum amyloid P component.
