5IDM:
reference: Cyclic di-GMP mediates a histidine kinase/phosphatase switch by noncovalent domain cross-linking., Dubey BN, Lori C, Ozaki S, Fucile G, Plaza-Menacho I, Jenal U, Schirmer T, Sci Adv. 2016 Sep 16;2(9):e1600823. doi: 10.1126/sciadv.1600823. eCollection 2016, Sep. PMID: 27652341

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