2Q0O:
reference: Structural basis for antiactivation in bacterial quorum sensing., Chen G, Jeffrey PD, Fuqua C, Shi Y, Chen L, Proc Natl Acad Sci U S A. 2007 Oct 16;104(42):16474-9. Epub 2007 Oct 5. PMID: 17921255

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