NMR studies and semi-empirical energy calculations for cyclic ADP-ribose.
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.
Rutherford
T J
TJ
School of Chemistry, University of Birmingham, Edgbaston, UK. t.j.rutherford@bham.ac.uk
Wilkie
J
J
Vu
C Q
CQ
Schnackerz
K D
KD
Jacobson
M K
MK
Gani
D
D
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
D011522:Protons; D036563:Cyclic ADP-Ribose; D000246:Adenosine Diphosphate Ribose