A study of the conformational state of the ATP gamma-p-azidoanilide-Mn2+ complex by NMR and atom-atomic potential methods
Abramova, T.V.; Vorob'ev, I.N.; Dashkevich, E.I.; Lebedev, A.V.
Bioorganicheskaia Khimiia 15(4): 514-526
1989
ISSN/ISBN: 0132-3423 PMID: 2751709 Document Number: 334100
By means of H1 and P31 spin-lattice relaxation and atom-atomic potentials method it is shown that in aquous solution the ATP gamma-p-azidoanilide--Mn2+ complex occurs mainly as a mixture of two conformers in the ratio of 60:40. They both possess folded conformations with distances between aromatic rings 5-6 A, and adenine residue anti-oriented, the ribose and triphosphate chain conformations are 3E and gg, g'g', g'g', respectively, in the major conformer, and 2E and g'g', g'g', g'g' in the second conformer. Mn2+ ion forms 2-3 complexes with each conformer (the cation being differently coordinated) by substituting phosphoryl oxygens or N7 atoms of adenine for two water molecules in the hydration shell of the cation. Magnesium ion forms inner-sphere complexes with two out of four ion-coordination centres (P alpha, P beta, P gamma, N7(A] and outer-sphere complexes with two other centres.