4L1T:
reference: Fluorogenic small molecules requiring reaction with a specific protein to create a fluorescent conjugate for biological imaging-what we know and what we need to learn., Baranczak A, Connelly SP, Liu Y, Choi S, Grimster NP, Powers ET, Wilson IA, Kelly JW, Biopolymers. 2013 Sep 19. doi: 10.1002/bip.22407. PMID: 24105107

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