5UPB:
reference: Swit_4259, an acetoacetate decarboxylase-like enzyme from Sphingomonas wittichii RW1., Mydy LS, Mashhadi Z, Knight TW, Fenske T, Hagemann T, Hoppe RW, Han L, Miller TR, Schwabacher AW, Silvaggi NR, Acta Crystallogr F Struct Biol Commun. 2017 Dec 1;73(Pt 12):672-681. doi:, 10.1107/S2053230X17015862. Epub 2017 Nov 14. PMID: 29199988

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