Assessing the reliability of density functional methods in the conformational study of polypeptides: the treatment of intraresidue nonbonding interactions |
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Authors: | Improta Roberto Barone Vincenzo |
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Affiliation: | Dipartimento di Chimica, Università Federico II, Complesso Universitario Monte S. Angelo, Via Cintia, I-80126 Napoli, Italy. |
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Abstract: | 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. |
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Keywords: | dipeptide analog helical conformers density functionals noncovalent interactions |
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