4BWW:
reference: High-resolution crystal structure of spin labelled (T21R1) azurin from Pseudomonas aeruginosa: a challenging structural benchmark for in silico spin labelling algorithms., Florin N, Schiemann O, Hagelueken G, BMC Struct Biol. 2014 May 29;14(1):16. PMID: 24884565

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