2TSB:
reference: Mutant Met121Ala of Pseudomonas aeruginosa azurin and its azide derivative: crystal structures and spectral properties., Tsai LC, Bonander N, Harata K, Karlsson G, Vanngard T, Langer V, Sjolin L, Acta Crystallogr D Biol Crystallogr. 1996 Sep 1;52(Pt 5):950-8. PMID: 15299604

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