Crystal and Solution Structure of 5′-O-(Guanosine-2′-O-Phosphonomethyl)Cytidine, an Isopolar Nonisosteric Phosphonate Analog Of GpC

Abstract

X-Ray crystal structure of 5′-O-(guanosine-2′-O-phosphonomethyl)-cytidine (G-p_cC(2′-5′)) was determined. The structural unit involves two molecules cf G-p_cC(2′-5′), differing both in the conformation of the phosphonate internucleotide linkage and in the intramolecular base-plane distances (3.6 Å; 3.3 Å), and fourteer molecules of water. The crystal data of G-p_cC(2′-5′) are discussed along with those obtained from NMR spectra.