2KAF:
reference: SARS coronavirus unique domain: three-domain molecular architecture in solution and RNA binding., Johnson MA, Chatterjee A, Neuman BW, Wuthrich K, J Mol Biol. 2010 Jul 23;400(4):724-42. Epub 2010 May 21. PMID: 20493876

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