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Conformational analysis by bond orbitals with delocalization corrections: Rotation of the ser‐195 side chain in α‐chymotrypsin
Author(s) -
Surján Peter R.,
NáraySzabó Gábor,
Mayer István
Publication year - 1982
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.560220507
Subject(s) - antibonding molecular orbital , delocalized electron , atomic orbital , chemistry , localized molecular orbitals , computational chemistry , molecular orbital , rotation (mathematics) , bond order , molecule , order (exchange) , molecular physics , hydrogen bond , chemical physics , linear combination of atomic orbitals , physics , bond length , quantum mechanics , mathematics , electron , geometry , organic chemistry , finance , economics
A recently developed procedure for calculation of tails of localized molecular orbitals is applied in order to obtain approximate rotational potential curves. In order to calculate reliable rotational barriers, tails, originating from direct interactions between bonding and antibonding strictly localized orthogonal orbitals, have to be determined. This finding permits us to develop a fast approximate SCF semiempirical procedure offering a reliable tool for studying conformational problems in rather large (bio)molecules. As a first example, a model of the active site of α‐chymotrypsin was examined. According to our calculations, a hydrogen bond between Ser‐195 and His‐57 should exist.