TY - JOUR
T1 - Chemical shielding and electric field gradient tensors of disodium 5′-adenosine triphosphate trihydrate determined by solid-state NMR spectroscopy and ab initio calculations
AU - Singh, Gurpreet
AU - Phalgune, Usha D.
AU - Madhu, Perunthiruthy K.
AU - Nielsen, Niels Christian
AU - Ganapathy, Subramanian
PY - 2022/6
Y1 - 2022/6
N2 - The tri-phosphate and sodium ion environments in well crystallized disodium 5′adenosine triphosphate trihydrate (ATP•3H
2O) are investigated using high-resolution solid-state NMR spectroscopy and ab initio calculations. The six inequivalent phosphorus sites resolved in
31P MAS spectra have been assigned on the basis of experimentally obtained results and theoretical ab initio quantum chemical calculations of
31P chemical shielding tensors with increased numerical accuracy. Aided by
31P-
31P dipolar connectivity established in DQ-SQ correlation experiment and DFT calculations carried out at the B3LYP/(aug-cc-pDVZ(3s,2p,1d), 6–31G(d,p)) level, phosphorus resonance assignments in MAS spectra have been made and the
31P chemical shielding anisotropies and tensor orientations in the molecule-fixed frame have been determined.
31P shielding tensors are found to be oriented with the most shielded direction nearly perpendicular to the O-P-O plane involving the two adjoining oxygens. The complete resolution of the four sodium sites has been achieved from 3Q-MAS experiments performed at 7.05 T and this has enabled
23Na quadrupole parameters to be determined experimentally and compared with theoretical calculations. Besides aiding a partial resonance assignment of the
23Na 3Q-MAS spectrum, our HF/6–311++G(2d,2p) calculations of
23Na EFG tensors show that for two sodium sites which are tightly coordinated the orientation of the EFG tensor is distinct. These exhibit unique directions along which the field gradient is the smallest and largest.
AB - The tri-phosphate and sodium ion environments in well crystallized disodium 5′adenosine triphosphate trihydrate (ATP•3H
2O) are investigated using high-resolution solid-state NMR spectroscopy and ab initio calculations. The six inequivalent phosphorus sites resolved in
31P MAS spectra have been assigned on the basis of experimentally obtained results and theoretical ab initio quantum chemical calculations of
31P chemical shielding tensors with increased numerical accuracy. Aided by
31P-
31P dipolar connectivity established in DQ-SQ correlation experiment and DFT calculations carried out at the B3LYP/(aug-cc-pDVZ(3s,2p,1d), 6–31G(d,p)) level, phosphorus resonance assignments in MAS spectra have been made and the
31P chemical shielding anisotropies and tensor orientations in the molecule-fixed frame have been determined.
31P shielding tensors are found to be oriented with the most shielded direction nearly perpendicular to the O-P-O plane involving the two adjoining oxygens. The complete resolution of the four sodium sites has been achieved from 3Q-MAS experiments performed at 7.05 T and this has enabled
23Na quadrupole parameters to be determined experimentally and compared with theoretical calculations. Besides aiding a partial resonance assignment of the
23Na 3Q-MAS spectrum, our HF/6–311++G(2d,2p) calculations of
23Na EFG tensors show that for two sodium sites which are tightly coordinated the orientation of the EFG tensor is distinct. These exhibit unique directions along which the field gradient is the smallest and largest.
KW - Adenosine triphosphate
KW - Interaction tensors
KW - Nucleotide
KW - Solid-state NMR
KW - ab initio calculations
UR - http://www.scopus.com/inward/record.url?scp=85163942896&partnerID=8YFLogxK
U2 - 10.1016/j.jmro.2022.100051
DO - 10.1016/j.jmro.2022.100051
M3 - Journal article
SN - 1090-7807
VL - 10-11
JO - Journal of Magnetic Resonance
JF - Journal of Magnetic Resonance
M1 - 100051
ER -