4MX3:
reference: PKA RIalpha Homodimer Structure Reveals an Intermolecular Interface with Implications for Cooperative cAMP Binding and Carney Complex Disease., Bruystens JG, Wu J, Fortezzo A, Kornev AP, Blumenthal DK, Taylor SS, Structure. 2014 Jan 7;22(1):59-69. doi: 10.1016/j.str.2013.10.012. Epub 2013 Dec , 5. PMID: 24316401

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