title: NMR studies and semi-empirical energy calculations for cyclic ADP-ribose.
abstract: A possible pH-dependent conformational switch was investigated for cyclic ADP-ribose. NMR signals for the exchangeable protons were observed in H2O at low temperature, but there was no direct evidence for the protonation of N-3 at neutral pH that has previously been postulated. MNDO calculations indicated that pH dependent 31P chemical shift changes are attributable to protonation of the phosphate adjacent to the N-1 of adenine, and not due to trans-annular hydrogen bonding with a protonated N-3.
authors.affiliation: School of Chemistry, University of Birmingham, Edgbaston, UK. t.j.rutherford@bham.ac.uk
authors.forename: T J
authors.initials: TJ
authors.lastname: Rutherford
authors.forename: J
authors.initials: J
authors.lastname: Wilkie
authors.forename: C Q
authors.initials: CQ
authors.lastname: Vu
authors.forename: K D
authors.initials: KD
authors.lastname: Schnackerz
authors.forename: M K
authors.initials: MK
authors.lastname: Jacobson
authors.forename: D
authors.initials: D
authors.lastname: Gani
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000031:analogs & derivatives* / Q000737:chemistry*; D036563:Cyclic ADP-Ribose; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011522:Protons; D013816:Thermodynamics
chemical_list: D011522:Protons; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose