3FLD:
reference: A Novel Fold in the TraI Relaxase-Helicase C-Terminal Domain Is Essential for Conjugative DNA Transfer., Guogas LM, Kennedy SA, Lee JH, Redinbo MR, J Mol Biol. 2009 Feb 20;386(2):554-68. Epub 2008 Dec 30. PMID: 19136009

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