Modeling of peptide–silica interaction based on four-body corrected fragment molecular orbital (FMO4) calculations

We have applied the four-body corrected fragment molecular orbital (FMO4) method to the investigation of the interaction between an artificially designed peptide, with sequence of Arg1-Lys2-Leu3-Pro4-Asp5-Ala6 [Sano et al., Langmuir, 21 (2005) 3090], and the silica surface modeled by a large cluster model including 257 silicon atoms. The second-order Mّller-Plesset perturbation calculation was accelerated by the Cholesky decomposition with adaptive metric technique (CDAM-MP2). Systematic analyses were made for inter-fragment interaction energies (IFIEs) with and without a statistical correction for screening. As the result, the importance of three charged residues (Arg1, Lys2 and Asp5) in the peptide-silica interaction was illuminated.