Ab initio simulation of the effect of the potential of water on the electronic structure of arginine
As a part of the task of constructing the equivalent potential of water in order to obtain a reliable electronic structure for a protein, the equivalent potential of water for an arginine molecule was constructed by performing first-principles, all-electron, ab initio calculations. The process consisted of three steps. First, the electronic structure of arginine was calculated using a free cluster calculation. Then, the minimum-energy geometric structure of the system Arg(+)+9H(2)O was found using free cluster calculations. Then, based on the optimized geometric structure of the Arg(+)+9H(2)O system, the electronic structure of Arg(+) in the potential of water was calculated using the SCCE method. Finally, by performing SCCE calculations, the effect of water on the electronic structure of Arg+ was simulated with dipoles. The results show that the effect of water on the electronic structure of Arg(+) is to broaden the energy gap tenfold, and to increase the eight eigenvalues below the HOMO by about 0.0546 Ry on average. The water potential can be accurately simulated using dipoles.
water electronic structure arginine free cluster calculation self-consistent cluster-embedding calculation