Replication protein A 14 kDa subunit is a protein that in humans is encoded by the RPA3 gene. RPA is a single-stranded DNA-binding protein that is conserved in eukaryotes and plays essential roles in the metabolism of nucleic acids. Unlike helicase, RPA does not separate strands but binds and protects exposed single-stranded DNA to prevent secondary structure formation and degradation. RPA is usually considered to be the functional equivalent of bacterial single-stranded DNA-binding proteins (SSB), although it is much more complex structurally in eukaryotic cells.
Interactions RPA3 has been shown to interact with replication protein A1 and replication protein A2. Together, they form a heterotrimeric complex that contributes to the direct binding of single-stranded DNA during replication, homologous recombination, nucleoetide excision repair, and mismatch repair. RPA3 can directly contact ssDNA on the 3' side of a substrate, and this polarity is crucial for the positioning and stability of nucleases that are involved in excision repair
See also Single-stranded binding protein Replication protein A Replication protein A1 Replication protein A2
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