2A0I:
reference: Inter- and intramolecular determinants of the specificity of single-stranded DNA binding and cleavage by the f factor relaxase., Larkin C, Datta S, Harley MJ, Anderson BJ, Ebie A, Hargreaves V, Schildbach JF, Structure (Camb) 2005 Oct;13(10):1533-44. PMID: 16216584

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