Conformation, hydrogen bonding and aggregate formation of guanosine 5'-monophosphate and guanosine in dimethylsulfoxide.
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.
West
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Division of Earth and Physical Sciences, University of Texas at San Antonio 78249.
Garza
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Winchester
W R
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Walmsley
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JA
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
D011522:Protons; D000644:Quaternary Ammonium Compounds; D006151:Guanosine; D007291:Inosine Monophosphate; D006157:Guanosine Monophosphate; C009405:tetrabutylammonium; D004121:Dimethyl Sulfoxide