3X2V:
reference: Protein Kinase A Catalytic Subunit Primed for Action: Time-Lapse Crystallography of Michaelis Complex Formation., Das A, Gerlits O, Parks JM, Langan P, Kovalevsky A, Heller WT, Structure. 2015 Dec 1;23(12):2331-40. doi: 10.1016/j.str.2015.10.005. Epub 2015, Nov 12. PMID: 26585512

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