5X6K:
reference: Structural analyses of adenylate kinases from Antarctic and tropical fishes for understanding cold adaptation of enzymes., Moon S, Kim J, Bae E, Sci Rep. 2017 Nov 22;7(1):16027. doi: 10.1038/s41598-017-16266-9. PMID: 29167503

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