Complex sentence: Replication protein A (RPA) is a protein that binds single stranded DNA in eukaryotic cells during replication and prevents it from winding back on itself or from forming secondary structures.
Split into simpler sentences: Replication protein A (RPA) is a protein that binds single-stranded DNA in eukaryotic cells. During DNA replication, RPA prevents single-stranded DNA (ssDNA) from winding back on itself or from forming secondary structures.