3OAB:
reference: Enhanced Specificity of Mint Geranyl Pyrophosphate Synthase by Modifying the R-Loop Interactions., Hsieh FL, Chang TH, Ko TP, Wang AH, J Mol Biol. 2010 Oct 19. PMID: 20965200

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