Cell surface-associated protein implicated in virulence. Promotes bacterial attachment exclusively to the gamma-chain of human fibrinogen. Induces formation of bacterial clumps, which diminish the ability of group IIA phospholipase A2 to cause bacterial phospholipid hydrolysis and killing. Significantly decreases macrophage phagocytosis possibly thanks to the clumps, clumped bacteria being too large to be phagocytosed. Dominant factor responsible for human platelet aggregation, which may be an important mechanism for initiating infective endocarditis (By similarity). Anchored to the cell wall by sortase A (By similarity). Belongs to the serine-aspartate repeat-containing protein (SDr) family.