1HLP:
reference: Structural Features That Stabilize Halophilic Malate Dehydrogenase from an Archaebacterium., Dym O, Mevarech M, Sussman JL, Science. 1995 Mar 3;267(5202):1344-1346. PMID: 17812611

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