3UI2:
reference: Chromodomains read the arginine code of post-translational targeting., Holdermann I, Meyer NH, Round A, Wild K, Sattler M, Sinning I, Nat Struct Mol Biol. 2012 Jan 8;19(2):260-3. doi: 10.1038/nsmb.2196. PMID: 22231402

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