2TBS:
reference: Cold adaption of enzymes: structural comparison between salmon and bovine trypsins., Smalas AO, Heimstad ES, Hordvik A, Willassen NP, Male R, Proteins 1994 Oct;20(2):149-66. PMID: 7846025

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