5B0U:
reference: Crystal structure of nanoKAZ: The mutated 19 kDa component of Oplophorus luciferase catalyzing the bioluminescent reaction with coelenterazine., Tomabechi Y, Hosoya T, Ehara H, Sekine S, Shirouzu M, Inouye S, Biochem Biophys Res Commun. 2016 Jan 29;470(1):88-93. doi:, 10.1016/j.bbrc.2015.12.123. Epub 2015 Dec 30. PMID: 26746005

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