3PKP:
reference: Expanding the Nucleotide and Sugar 1-Phosphate Promiscuity of Nucleotidyltransferase RmlA via Directed Evolution., Moretti R, Chang A, Peltier-Pain P, Bingman CA, Phillips GN Jr, Thorson JS, J Biol Chem. 2011 Apr 15;286(15):13235-43. Epub 2011 Feb 11. PMID: 21317292

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