title: Equivalent potential of water molecules for electronic structure of glutamic acid.
abstract: The fundamental importance of the electronic structure of molecules is widely recognized. To get reliable electronic structure of protein in aqueous solution, it is necessary to construct a simple, easy-use equivalent potential of water molecules for protein's electronic structure calculation. Here, the first-principles, all-electron, ab initio calculations have been performed to construct the equivalent potential of water molecules for the electronic structure of glutamic acid, which is a hydrophilic amino acid and is negatively charged (Glu(-)) in neutral water solution. The main process of calculation consists of three steps. Firstly, the geometric structure of the cluster containing Glu(-) and water molecules is calculated by free cluster calculation. Then, based on the geometric structure, the electronic structure of Glu(-) with the potential of water molecules is calculated using the self-consistent cluster-embedding method. Finally, the electronic structure of Glu(-) with the potential of dipoles is calculated. Our calculations show that the major effect of water molecules on Glu(-)'s electronic structure is lowering the occupied electronic states by about 0.017 Ry, and broadening energy gap by 12%. The effect of water molecules on the electronic structure of Glu(-) can be well simulated by dipoles potential.
authors.affiliation: Department of Physics, Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, People's Republic of China. zt247812@163.com
authors.forename: Tian
authors.initials: T
authors.lastname: Zhang
authors.forename: Haoping
authors.initials: H
authors.lastname: Zheng
authors.forename: Shu
authors.initials: S
authors.lastname: Yan
mesh_terms: D018698:Glutamic Acid / Q000737:chemistry*; D008958:Models, Molecular; D014867:Water / Q000737:chemistry*
chemical_list: D014867:Water; D018698:Glutamic Acid