title: Conformation, hydrogen bonding and aggregate formation of guanosine 5'-monophosphate and guanosine in dimethylsulfoxide.
abstract: The tetrabutylammonium salt of guanosine 5'-monophosphate (5'-GMP) dissolves in DMSO-d6 forming aggregated species which exhibit some properties of reverse micelles. 1H NOESY experiments show that the 5'-GMP adopts the syn conformation about the glycosidic bond. Molecular mechanics calculations reveal a stable structure with this conformation in which the phosphate group and the amino group of the base are in close enough proximity to hydrogen bond. In contrast inosine 5'-monophosphate in DMSO-d6, which has no NH2 group for hydrogen bond stabilization of the syn conformation, is shown by NMR to have the anti structure. Guanosine in DMSO-d6 behaves differently from 5'-GMP. Guanosine adopts the anti conformation and forms a symmetric dimer via hydrogen bonding between the N3 and NH2 of the bases.
authors.affiliation: Division of Earth and Physical Sciences, University of Texas at San Antonio 78249.
authors.forename: R T
authors.initials: RT
authors.lastname: West
authors.forename: L A
authors.initials: LA
authors.lastname: Garza
authors.forename: W R
authors.initials: WR
authors.lastname: Winchester
authors.forename: J A
authors.initials: JA
authors.lastname: Walmsley
mesh_terms: D004121:Dimethyl Sulfoxide; D006151:Guanosine / Q000737:chemistry*; D006157:Guanosine Monophosphate / Q000737:chemistry*; D006860:Hydrogen Bonding; D007291:Inosine Monophosphate / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D009690:Nucleic Acid Conformation; D011522:Protons; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D012995:Solubility
chemical_list: D011522:Protons; D000644:Quaternary Ammonium Compounds; D006151:Guanosine; D007291:Inosine Monophosphate; D006157:Guanosine Monophosphate; C009405:tetrabutylammonium; D004121:Dimethyl Sulfoxide