Cell surface-associated calcium-binding protein which plays an important role in adhesion and pathogenesis. Contributes to the resistance to killing by innate immune components in blood and thus attenuates bacterial clearance by interacting with host complement factor H/CFAH and modulating its activity (PubMed:28258151). Inhibits also bacterial opsonization and killing by interacting with host complement regulator C4BPA and thus inhibiting classical complement pathway activation (By similarity). Interacts with host complement factor H/CFAH (via C-terminus) (PubMed:28258151). Interacts with host complement regulator C4BPA (By similarity). Anchored to the cell wall by sortase A (By similarity). Belongs to the serine-aspartate repeat-containing protein (SDr) family.