第一性原理计算水对缬氨酸电子结构的等效势

Ab Initio Calculation of Equivalent Potential of Water for Electronic Structure of Valine

摘要:

用第一性原理、全电子、从头计算方法构造了水溶液对缬氨酸（Val）电子结构的等效势.首先用自由团簇计算法得到能量最低时水分子与缬氨酸的相对空间位形，然后用团簇埋入自洽计算(SCCE)方法计算缬氨酸在水分子势下的电子结构，最后用偶极子势代替水分子势.结果表明：由于水溶液的存在，缬氨酸费米面下八个能级每个能级平均上升了约0.775 5 eV；水溶液对缬氨酸电子结构的影响可以很好地被偶极子势模拟.因此,所得的偶极子势可以直接运用到水溶液中蛋白质电子结构的计算中.

Abstract:

The equivalent potential of water for the electronic structure of valine (Val) was constructed on the basis of the first principles, all electron, ab initio calculations. The process involved three steps. First, a search for the minimum energy configuration of the system Val+7H2O was carried out by free cluster calculation. Then, the electronic structure of valine with the potential of water molecules was calculated with the self consistent cluster embedding (SCCE) method. Finally, the effect of water was simulated on valine by dipoles. Results show that the major effect of water on the electronic structure of valine is to raise the eigenvalues of eight orbitals under Fermi surface by about 0.775 5 eV on average. The effect of water on the electronic structure of valine can be well simulated by dipoles. The equivalent potential obtained can be applied directly to the calculation of the electronic structures of proteins in solution.