1O55:
reference: Molecular structure of two crystal forms of cyclic triadenylic acid at 1A resolution., Gao YG, Robinson H, Guan Y, Liaw YC, van Boom JH, van der Marel GA, Wang AH, J Biomol Struct Dyn 1998 Aug;16(1):69-76. PMID: 9745896

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