title: Interaction of purine nucleotides with cobalt-hexammine, cobalt-pentammine and cobalt-tetrammine cations. Evidence for the rigidity of adenosine and flexibility of guanosine and deoxyguanosine sugar conformations.
abstract: The interaction of adenosine-5'-monophosphate (5'-AMP), guanosine-5'-monophosphate (5'-GMP) and 2'-deoxyguanosine-5'-monophosphate (5'-dGMP) with the [Co(NH3)6]3+, [Co(NH3)5Cl]2+ and [Co(NH3)4Cl2]+ cations has been investigated in aqueous solution with metal/nucleotide ratios (r) of 1/2, 1 and 2 at neutral pH. The solid complexes have been isolated and characterized by FT-IR and 1H-NMR spectroscopy. The complexes are polymeric in nature both in the crystalline solid and aqueous solution. The binding of the cobalt-hexammine cation is indirectly (via NH3) through the N-7 and the PO3(2-) groups of the AMP and via O-6, N-7 and the PO3(2-) of the GMP and dGMP anions (outer-sphere). The cobalt-pentammine and cobalt-tetrammine bindings are through the phosphate groups (inner-sphere) and the N-7 site (outer-sphere) of these nucleotide anions. The ribose moiety shows C2'-endo/anti conformation, in the free AMP and GMP anions as well as in the cobalt-ammine-AMP complexes, whereas a mixture of teh C2'-endo/anti and C3'-endo/anti sugar puckers were observed for the Co(NH3)6-GMP, Co(NH3)5-GMP and a C3'-endo/anti conformer for the Co(NH3)4-GMP complexes. The deoxyribose showed an O4'-endo/anti conformation for the free dGMP anion and a C3'-endo/anti for the Co(NH3)6-dGMP, Co(NH3)5-dGMP and Co(NH3)4-dGMP complexes.
authors.affiliation: Photobiophysics Research Center, University of Quebec, Trois-Rivieres, Canada.
authors.forename: H A
authors.initials: HA
authors.lastname: Tajmir-Riahi
mesh_terms: D000241:Adenosine / Q000737:chemistry*; D000249:Adenosine Monophosphate / Q000737:chemistry*; D002236:Carbohydrate Conformation; D003035:Cobalt / Q000737:chemistry*; D003848:Deoxyguanine Nucleotides / Q000737:chemistry*; D003849:Deoxyguanosine / Q000737:chemistry*; D003855:Deoxyribose / Q000737:chemistry*; D006151:Guanosine / Q000737:chemistry*; D006157:Guanosine Monophosphate / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008968:Molecular Conformation; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds; D012266:Ribose / Q000737:chemistry*; D013055:Spectrophotometry, Infrared
chemical_list: D003848:Deoxyguanine Nucleotides; D009942:Organometallic Compounds; D000644:Quaternary Ammonium Compounds; D006151:Guanosine; C030862:cobalt ammonium complex; C032300:hexaamminecobalt(II); D003035:Cobalt; D000249:Adenosine Monophosphate; C070882:cobalt-pentammine cation; D003855:Deoxyribose; D012266:Ribose; C007257:2'-deoxyguanosine 5'-phosphate; D006157:Guanosine Monophosphate; C070880:cobalt-tetrammine cation; D003849:Deoxyguanosine; D000241:Adenosine