1RXP:
reference: Solid-phase synthesis and SAR of 4-carboxy-2-azetidinone mechanism-based tryptase inhibitors., Sutton JC, Bolton SA, Davis ME, Hartl KS, Jacobson B, Mathur A, Ogletree ML, Slusarchyk WA, Zahler R, Seiler SM, Bisacchi GS, Bioorg Med Chem Lett 2004 May 3;14(9):2233-9. PMID: 15081015

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