4GOP:
reference: Structure and conformational change of a replication protein A heterotrimer bound to ssDNA., Fan J, Pavletich NP, Genes Dev. 2012 Oct 15;26(20):2337-47. doi: 10.1101/gad.194787.112. PMID: 23070815

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).