4PIG:
reference: Enhancing ubiquitin crystallization through surface-entropy reduction., Loll PJ, Xu P, Schmidt JT, Melideo SL, Acta Crystallogr F Struct Biol Commun. 2014 Oct 1;70(Pt 10):1434-42. doi:, 10.1107/S2053230X14019244. Epub 2014 Sep 25. PMID: 25286958

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