1NHK:
reference: The 1.9 A crystal structure of a nucleoside diphosphate kinase complex with adenosine 3',5'-cyclic monophosphate: evidence for competitive inhibition., Strelkov SV, Perisic O, Webb PA, Williams RL, J Mol Biol. 1995 Jun 9;249(3):665-74. PMID: 7783219

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