6BBZ:
reference: A low-barrier hydrogen bond mediates antibiotic resistance in a noncanonical catalytic triad., Kumar P, Serpersu EH, Cuneo MJ, Sci Adv. 2018 Apr 4;4(4):eaas8667. doi: 10.1126/sciadv.aas8667. eCollection 2018 , Apr. PMID: 29632894

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