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Ab initio quantum chemical calculation of electron density, electrostatic potential, and electric field of biomolecule based on fragment molecular orbital method
Author(s) -
Ishikawa Takeshi
Publication year - 2018
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.25535
Subject(s) - fragment molecular orbital , electric field , chemistry , ab initio , electrostatics , molecular dynamics , biomolecule , electron , electron density , charge density , computational chemistry , chemical physics , molecular physics , molecular orbital , physics , molecule , quantum mechanics , biochemistry , organic chemistry
Efficient quantum chemical calculations of electrostatic properties, namely, the electron density (EDN), electrostatic potential (ESP), and electric field (EFL), were performed using the fragment molecular orbital (FMO) method. The numerical errors associated with the FMO scheme were examined at the HF, MP2, and RI‐MP2 levels of theory using 4 small peptides. As a result, the FMO errors in the EDN, ESP, and EFL were significantly smaller than the magnitude of the electron correlation effects, which indicated that the FMO method provides sufficiently accurate values of electrostatic properties. In addition, an attempt to reduce the computational effort was proposed by combining the FMO scheme and a point charge approximation. The error due to this approximation was examined using 2 proteins, prion protein and human immunodeficiency virus type 1 protease. As illustrative examples, the ESP values at the molecular surface of these proteins were calculated at the MP2 level of theory.