TY - JOUR

T1 - New horizons of adenosinetriphosphate energetics arising from interaction with magnesium cofactor

AU - Tulub, Alexander A.

AU - Stefanov, V. E.

PY - 2008/10/1

Y1 - 2008/10/1

N2 - MD DFT:B3LYP (6-31G*z.ast;basis set, T = 310 K) method is used to study interactions [singlet (S) and triplet (T) reaction paths] between adenosinetriphosphate, ATP4-, and [Mg(H2O) 6]2+ in water environment, modeled with 78 water molecules. Computations reveal the appearance of low and high-energy states (stable, quasi-stable, and unstable), assigned to different spin symmetries. At the initial stage of interaction, ATP donates a part of its negative charge to the Mg complex making the Mg slightly charged. As a result, the original octahedral Mg complex loses two (S state) or four (T state) water molecules. Moving along S or T potential energy surfaces (PESs), Mg(H2O) 4 or Mg(H2O)2 display different ways of complexation with ATP. S path favors the formation of a stable chelate with the O1-O2 fragment of ATP triphosphate tail, whereas T path favors producing a single-bonded complex with the O2. The latter, being unstable, undergoes a further conversion into a spin-separated complex, also unstable, and two metastable S complexes, which finally arise in two stable, low-energy and high-energy, chelates. The spin-separated complex experiences rapid decomposition resulting in the production of a highly reactive adenosinemonophosphate ion-radical •AMP, early observed in the CIDNP experiment (Tulub 2006). Biological consequences of the findings are discussed.

AB - MD DFT:B3LYP (6-31G*z.ast;basis set, T = 310 K) method is used to study interactions [singlet (S) and triplet (T) reaction paths] between adenosinetriphosphate, ATP4-, and [Mg(H2O) 6]2+ in water environment, modeled with 78 water molecules. Computations reveal the appearance of low and high-energy states (stable, quasi-stable, and unstable), assigned to different spin symmetries. At the initial stage of interaction, ATP donates a part of its negative charge to the Mg complex making the Mg slightly charged. As a result, the original octahedral Mg complex loses two (S state) or four (T state) water molecules. Moving along S or T potential energy surfaces (PESs), Mg(H2O) 4 or Mg(H2O)2 display different ways of complexation with ATP. S path favors the formation of a stable chelate with the O1-O2 fragment of ATP triphosphate tail, whereas T path favors producing a single-bonded complex with the O2. The latter, being unstable, undergoes a further conversion into a spin-separated complex, also unstable, and two metastable S complexes, which finally arise in two stable, low-energy and high-energy, chelates. The spin-separated complex experiences rapid decomposition resulting in the production of a highly reactive adenosinemonophosphate ion-radical •AMP, early observed in the CIDNP experiment (Tulub 2006). Biological consequences of the findings are discussed.

KW - ATP

KW - MD DFT

KW - Mg complexes

UR - http://www.scopus.com/inward/record.url?scp=51849102857&partnerID=8YFLogxK

U2 - 10.1007/s00249-008-0337-5

DO - 10.1007/s00249-008-0337-5

M3 - Article

C2 - 18463860

AN - SCOPUS:51849102857

VL - 37

SP - 1309

EP - 1316

JO - European Biophysics Journal

JF - European Biophysics Journal

SN - 0175-7571

IS - 8

ER -