5TZF:
reference: The Streptomyces master regulator BldD binds c-di-GMP sequentially to create a functional BldD2-(c-di-GMP)4 complex., Schumacher MA, Zeng W, Findlay KC, Buttner MJ, Brennan RG, Tschowri N, Nucleic Acids Res. 2017 Apr 26. doi: 10.1093/nar/gkx287. PMID: 28449057

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