3X44:
reference: The structural and mutational analyses of O-ureido-L-serine synthase necessary for D-cycloserine biosynthesis., Uda N, Matoba Y, Oda K, Kumagai T, Sugiyama M, FEBS J. 2015 Jul 24. doi: 10.1111/febs.13386. PMID: 26207937

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