1WCR:
reference: Solution structure of enzyme IIA(Chitobiose) from the N,N'-diacetylchitobiose branch of the Escherichia coli phosphotransferase system., Tang C, Williams DC Jr, Ghirlando R, Clore GM, J Biol Chem. 2005 Mar 25;280(12):11770-80. Epub 2005 Jan 14. PMID: 15654077

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