The equivalent potential of water for electronic structure of aspartic acid

The equivalent potential of water for the electronic structure of aspartic acid (Asp − ) in solution is constructed by the first‐principles, all‐electrons, ab initio calculations. Aspartic acid is a hydrophilic amino acid which is negatively charged in neutral water solution. The main process of calculation consists of three steps. Firstly, the geometric structure of the cluster containing Asp − and water molecules is calculated by the free cluster calculation. Then, based on the obtained geometric structure, the electronic structure of Asp − with the potential of water molecules is calculated using the self‐consistent cluster‐embedding method. Finally, the electronic structure of Asp − with the potential of dipoles is calculated. The results show that the major effect of water on Asp − 's electronic structure is lowering the occupied molecular orbitals by about 0.02 Ry on average, and narrowing energy gap by 10.8%. The effect of water on the electronic structure of Asp − can be simulated by dipoles potential. © 2008 Wiley Periodicals, Inc.J Comput Chem, 2008.