3BTF:
reference: The crystal structures of the complexes between bovine beta-trypsin and ten P1 variants of BPTI., Helland R, Otlewski J, Sundheim O, Dadlez M, Smalas AO, J Mol Biol 1999 Apr 16;287(5):923-42. PMID: 10222201

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