2CBN:
reference: The crystal structure of the zinc phosphodiesterase from Escherichia coli provides insight into function and cooperativity of tRNase Z-family proteins., Kostelecky B, Pohl E, Vogel A, Schilling O, Meyer-Klaucke W, J Bacteriol. 2006 Feb;188(4):1607-14. PMID: 16452444

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