1NSK:
reference: The crystal structure of a human nucleoside diphosphate kinase, NM23-H2., Webb PA, Perisic O, Mendola CE, Backer JM, Williams RL, J Mol Biol 1995 Aug 25;251(4):574-87. PMID: 7658474

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