The DF-LCCSD(T0) correction of the .fi./.psi. force field dihedral parameters significantly influences the free energy profile of the alanine dipeptide

0369287 - ÚOCHB 2012 RIV NL eng J - Journal Article
Vymětal, Jiří - Vondrášek, Jiří
The DF-LCCSD(T0) correction of the .fi./.psi. force field dihedral parameters significantly influences the free energy profile of the alanine dipeptide.
Chemical Physics Letters. Roč. 503, 4/6 (2011), s. 301-304. ISSN 0009-2614. E-ISSN 1873-4448
R&D Projects: GA ČR GAP208/10/0725; GA MŠMT LC512; GA MŠMT(CZ) LH11020
Institutional research plan: CEZ:AV0Z40550506
Keywords : conformational preferences * quantum-mechanics * gas-phase * simulations * peptides
Subject RIV: CF - Physical ; Theoretical Chemistry
Impact factor: 2.337, year: 2011

The conformational behavior of small peptides is mostly dictated by backbone rigidity, in which the phi/psi torsions seem to play the most important role. We show that ab initio-based corrections of the torsion parameters in the FF-FOM force field determined by the DF-LCCSD(T0) method significantly influence the quality and minimum localization on the 2D free energy surface of the alanine dipeptide (AD) along the phi and psi coordinates of the backbone torsion angles. The populations of the individual conformers are in good agreement with the experimental results published recently on the AD through an analysis of the amide III band and the Raman skeletal vibrations. (C) 2011 Elsevier B.V. All rights reserved.
Permanent Link: http://hdl.handle.net/11104/0006738