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Assessing the reliability of density functional methods in the conformational study of polypeptides: The treatment of intraresidue nonbonding interactions
Author(s) -
Improta Roberto,
Barone Vincenzo
Publication year - 2004
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20062
Subject(s) - dipeptide , computation , density functional theory , computational chemistry , conformational isomerism , chemistry , range (aeronautics) , electron density , chemical physics , electrostatics , electron , materials science , physics , molecule , computer science , quantum mechanics , algorithm , amino acid , organic chemistry , biochemistry , composite material
The role of intraresidue interactions in determining the conformational behavior of polypeptides is analyzed by means of density functional and post‐Hartree–Fock computations on the alanine dipeptide analog and other model compounds. Our computations show that the accuracy of current density functionals is sufficient for H‐bond, electrostatic, inductive, and short‐range repulsive interactions, whereas medium‐range attractions between electron‐rich atoms and/or bonds are underestimated. This leads, in turn, to an underestimation of the stability of helical structures w.r.t. extended or folded conformers involving H‐bonds. Those results could pave the route for devising local ad hoc corrections able to significantly improve structural and dynamic predictions for polypeptides issuing from DFT computations. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1333–1341, 2004