1DQW:
reference: Anatomy of a proficient enzyme: the structure of orotidine 5'-monophosphate decarboxylase in the presence and absence of a potential transition state analog., Miller BG, Hassell AM, Wolfenden R, Milburn MV, Short SA, Proc Natl Acad Sci U S A 2000 Feb 29;97(5):2011-6. PMID: 10681417

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