TY - JOUR

T1 - The effect of the oxidative properties of [Mg(H2O)6] in the Triplet and Singlet States on the Energetics of Adenosine Triphosphate Cleavage

AU - Tulub, A. A.

AU - Stefanov, V. E.

N1 - Funding Information: This work was supported by the Ministry of Education and Science of the Russian Federation (Analytical Departmental Targeted Program “Development of Scientific Potential of Higher School,” project no. 2.1.1/485).

PY - 2009/12

Y1 - 2009/12

N2 - The interaction of the adenosine triphosphate (ATP) molecule (the ATP subsystem) with the magnesium complex [Mg(H2O)6] 2+ (the Mg subsystem) in the singlet (S) and triplet (T) states in an aqueous medium mimicked by 78 water molecules was studied by the molecular dynamics (density functional theory) method MD DFT:B3LYP with the 6-31G ** basis set at T = 310 K. Potential energy surfaces for the S (lowest-lying) and T (highest-lying) states are significantly separated in space. The Mg complex moves along these surfaces to approach either oxygen atoms of the β-α phosphate groups (O1-O2) (S PES) or oxygen atoms of α-β phosphate groups (O2-O3) (T PES). Chelation of the γ-beta; and beta;-alpha; phosphates yields, respectively, a stable lowenergy complex ([Mg (H2O)4-(O1-O2)ATP]2-) and a metastable high-energy complex ([Mg(H2O)2-(O2-3)ATP]2-), which differ in the number of water molecules surrounding the Mg atom. Crossing f two triplet PESs is accompanied by the formation of an unstable state characterized by redistribution of spins between the Mg and ATP subsystems. This state, sensitive to interaction with the 25Mg nuclear spin, induces an unpaired electron spin, which initiates the ATP cleavage by the ion-radical mechanism, yielding a reactive radical ion of adenosine monophosphate ( •AMP ̄), which was earlier found experimentally by the of chemically induced dynamic nuclear polarization (CIDNP) method. Biological aspects of the results obtained are discussed.

AB - The interaction of the adenosine triphosphate (ATP) molecule (the ATP subsystem) with the magnesium complex [Mg(H2O)6] 2+ (the Mg subsystem) in the singlet (S) and triplet (T) states in an aqueous medium mimicked by 78 water molecules was studied by the molecular dynamics (density functional theory) method MD DFT:B3LYP with the 6-31G ** basis set at T = 310 K. Potential energy surfaces for the S (lowest-lying) and T (highest-lying) states are significantly separated in space. The Mg complex moves along these surfaces to approach either oxygen atoms of the β-α phosphate groups (O1-O2) (S PES) or oxygen atoms of α-β phosphate groups (O2-O3) (T PES). Chelation of the γ-beta; and beta;-alpha; phosphates yields, respectively, a stable lowenergy complex ([Mg (H2O)4-(O1-O2)ATP]2-) and a metastable high-energy complex ([Mg(H2O)2-(O2-3)ATP]2-), which differ in the number of water molecules surrounding the Mg atom. Crossing f two triplet PESs is accompanied by the formation of an unstable state characterized by redistribution of spins between the Mg and ATP subsystems. This state, sensitive to interaction with the 25Mg nuclear spin, induces an unpaired electron spin, which initiates the ATP cleavage by the ion-radical mechanism, yielding a reactive radical ion of adenosine monophosphate ( •AMP ̄), which was earlier found experimentally by the of chemically induced dynamic nuclear polarization (CIDNP) method. Biological aspects of the results obtained are discussed.

UR - http://www.scopus.com/inward/record.url?scp=70350053569&partnerID=8YFLogxK

U2 - 10.1134/S0036023609070213

DO - 10.1134/S0036023609070213

M3 - Article

AN - SCOPUS:70350053569

VL - 54

SP - 1127

EP - 1134

JO - Russian Journal of Inorganic Chemistry

JF - Russian Journal of Inorganic Chemistry

SN - 0036-0236

IS - 7

ER -