1USY:
reference: Regulation of the hetero-octameric ATP phosphoribosyl transferase complex from Thermotoga maritima by a tRNA synthetase-like subunit., Vega MC, Zou P, Fernandez FJ, Murphy GE, Sterner R, Popov A, Wilmanns M, Mol Microbiol. 2005 Feb;55(3):675-86. PMID: 15660995

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