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PMC Physics B

, 1:18

First Online: 04 December 2008Received: 05 March 2008Accepted: 04 December 2008

Abstract

The Schlegel-Frisch ab initio molecular dynamics ADMP DFT:B3LYP, T = 310 K, is used to study complexation between adenosinetriphosphate ATP, ATP subsystem, and magnesium cofactor MgH2O6, Mg subsystem, in a water pool, modeled with 78 water molecules, in singlet S and triplet T states. The computations prove that the way of ATP cleavage is governed by the electron spin of Mg. In the S state Mg prefers chelation of γ-β-phosphate oxygens O1-O2, whereas in the T state it chelates β-α-phosphate oxygens O2-O3 or produces a single-bonded intermediate. Unlike the chelates, which initiate ionic reaction paths, the single-bonded intermediate starts off a free-radical path of ATP cleavage, yielding a highly reactive adenosinemonophosphate ion-radical, •AMP, earlier observed in the CIDNP Chemically Induced Dynamic Nuclear Polarization experiment A.A. Tulub, 2006. The free-radical path is highly sensitive to Mg nuclear spin, which through a hyperfine interaction favors the production of unpaired electron spins. The unique role of Mg in ATP cleavage comes through its ability to serve as a unique redox center, initially accepting an electron from ATP and then giving it back to products. Redox activity of Mg differs for T and S states and affects the number of coordinated water molecules. The findings give a new insight into the NTP N = nucleoside energetics and assembly of NTP-operating molecules, including proteins.

PACS codes: 87.15.-v

Electronic supplementary materialThe online version of this article doi:10.1186-1754-0429-1-18 contains supplementary material, which is available to authorized users.

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Author: Alexander A Tulub

Source: https://link.springer.com/







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