1UUK:
reference: Plasmid P1 RepA is homologous to the F plasmid RepE class of initiators., Sharma S, Sathyanarayana BK, Bird JG, Hoskins JR, Lee B, Wickner S, J Biol Chem 2004 Feb 13;279(7):6027-34. Epub 2003 Nov 21. PMID: 14634015

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