4Q5O:
reference: Crystal Structure of the Ectoine Hydroxylase: a Snapshot of the Active Site., Hoeppner A, Widderich N, Lenders M, Bremer E, Smits SH, J Biol Chem. 2014 Aug 29. pii: jbc.M114.576769. PMID: 25172507

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