As part of the replication protein A (RPA/RP-A), a single-stranded DNA-binding heterotrimeric complex, may play an essential role in DNA replication, recombination and repair. Binds and stabilizes single-stranded DNA intermediates, preventing complementary DNA reannealing and recruiting different proteins involved in DNA metabolism (By similarity). Stimulates the activity of a cognate strand exchange protein (SEP1). Component of the heterotrimeric canonical replication protein A complex (RPA). The N-terminus is blocked. Present with 4280 molecules/cell in log phase SD medium. Belongs to the replication factor A protein 3 family.