Bespalova S V, Mishchenko A M, Shatalov V M
Donetsk State University, ul. Shchorsa 46, Donetsk, 83050 Ukraine.
Biofizika. 2002 Mar-Apr;47(2):236-44.
The mechanism underlying the excitation of the hydrogen bond with ATP hydrolysis was considered. Coulomb interactions of the proton of the hydrogen bond A-H...B with the electrical field of the covalent bond of ADP-P were calculated. It was shown that the electrical field of the covalent bond of ADP-P excites oscillations of the proton in the complex with the hydrogen bond A-H...B and displaces it from the equilibrium towards the covalent bond. The distortion of the potential curve depends on a change in the length of the covalent bond of ADP-P. Adiabatic potentials U0 and UN of the ADP-P system were calculated, which correspond to the ground and excited states of the H-bond proton. It was found that as the length of the bond of ADP-P (rho) increases, the branches of the adiabatic potential U0(rho) and UN(rho) intersect. At the intersection point, the system can transit to the branch UN(rho), which can lead to a reduction of the barrier and a break of the covalent bond of ADP-P. Presumably, this mechanism is universal for processes of transformation of the chemical energy of ATP to the energy of excited hydrogen bond, a mechanism for the maintenance of heat balance and reduction of entropy in a living organism.
研究了ATP水解激发氢键的潜在机制。计算了氢键A-H...B的质子与ADP-P共价键电场的库仑相互作用。结果表明,ADP-P共价键的电场激发了与氢键A-H...B形成复合物的质子振荡,并使其从平衡位置向共价键方向移动。势能曲线的畸变取决于ADP-P共价键长度的变化。计算了ADP-P系统的绝热势U0和UN,它们分别对应于氢键质子的基态和激发态。研究发现,随着ADP-P键长度(rho)的增加,绝热势U0(rho)和UN(rho)的分支相交。在交点处,系统可以跃迁到分支UN(rho),这可能导致势垒降低和ADP-P共价键断裂。据推测,这种机制对于将ATP化学能转化为激发氢键能量的过程是普遍适用的,是维持生物体热平衡和降低熵的一种机制。