title: Drastic Compensation of Electronic and Solvation Effects on ATP Hydrolysis Revealed through Large-Scale QM/MM Simulations Combined with a Theory of Solutions.
abstract: Hydrolysis of adenosine triphosphate (ATP) is the "energy source" for a variety of biochemical processes. In the present work, we address key features of ATP hydrolysis: the relatively moderate value (about -10 kcal/mol) of the standard free energy, ΔGhyd, of reaction and the insensitivity of ΔGhydto the number of excess electrons on ATP. We conducted quantum mechanical/molecular mechanical simulation combined with the energy-representation theory of solutions to analyze the electronic-state and solvation contributions to ΔGhyd. It was revealed that the electronic-state contribution in ΔGhydis largely negative (favorable) upon hydrolysis, due to the reduction of electrostatic repulsion accompanying the breakage of the P-O bond. In contrast, the solvation effect was found to be strongly more favorable on the reactant side. Thus, we showed that a drastic compensation of the two opposite effects takes place, leading to the modest value of ΔGhydat each number of excess electrons examined. The computational analyses were also conducted for pyrophosphate ions (PPi), and the parallelism between the ATP and PPi hydrolyses was confirmed. Classical molecular dynamics simulation was further carried out to discuss the effect of the solvent environment; the insensitivity of ΔGhydto the number of excess electrons was seen to hold in solvent water and ethanol.
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , Sendai, Miyagi 980-8578, Japan.
authors.forename: Hideaki
authors.identifier: 0000-0002-4412-4115
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , Sendai, Miyagi 980-8578, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Umino
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , Sendai, Miyagi 980-8578, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Miki
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Ishizuka
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Shu
authors.initials: S
authors.lastname: Maeda
authors.affiliation: Department of Chemistry, Graduate School of Science, Tohoku University , Sendai, Miyagi 980-8578, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Morita
authors.affiliation: Department of Materials Processing, Graduate School of Engineering, Tohoku University , Sendai, Miyagi 980-8579, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering Science, Osaka University , Toyonaka, Osaka 560-8531, Japan.
authors.forename: Nobuyuki
authors.identifier: 0000-0001-7176-441X
authors.initials: N
authors.lastname: Matubayasi
mesh_terms: D000255:Adenosine Triphosphate / Q000737:chemistry*; D004583:Electrons; D004735:Energy Transfer; D006868:Hydrolysis; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D012997:Solvents / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
chemical_list: D012997:Solvents; D014867:Water; D000255:Adenosine Triphosphate