Final answer:
The RPA protein binds to single-stranded DNA during replication to stabilize it and keep the strands apart, facilitating effective DNA synthesis by preventing secondary structures and re-annealing.
Step-by-step explanation:
The function of the RPA protein in replication is to bind to single-stranded DNA (ssDNA), which occurs when the DNA helix is unwound during the replication process. This binding stabilizes the ssDNA and prevents it from forming secondary structures or re-annealing to its complementary strand, ensuring that it stays in a linear form suitable for use as a template for DNA synthesis. By coating the ssDNA, RPA helps maintain the integrity of the replication fork, which is crucial for the processive replication machinery, including DNA polymerases, to function effectively. RPA has a central role in various DNA metabolic processes, including replication, repair, and recombination.