2MKP:
reference: Conformation of the critical pH sensitive region of troponin depends upon a single residue in troponin I., Robertson IM, Pineda-Sanabria SE, Holmes PC, Sykes BD, Arch Biochem Biophys. 2013 Dec 12. pii: S0003-9861(13)00368-8. doi:, 10.1016/j.abb.2013.12.003. PMID: 24333682

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