2CLT:
reference: Crystal structure of an active form of human MMP-1., Iyer S, Visse R, Nagase H, Acharya KR, J Mol Biol. 2006 Sep 8;362(1):78-88. Epub 2006 Aug 4. PMID: 16890240

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