Title
Free-energy calculations of residue mutations in a tripeptide using various methods to overcome inefficient sampling.
Abstract
Previous free-energy calculations have shown that the seemingly simple transformation of the tripeptide KXK to KGK in water holds some unobvious challenges concerning the convergence of the forward and backward thermodynamic integration processes (i.e., hysteresis). In the current study, the central residue X was either alanine, serine, glutamic acid, lysine, phenylalanine, or tyrosine. Interestingly, the transformation from alanine to glycine yielded the highest hysteresis in relation to the extent of the chemical change of the side chain. The reason for that could be attributed to poor sampling of phi 2/psi 2 dihedral angles along the transformation. Altering the nature of alanine's C-beta atom drastically improved the sampling and at the same time led to the identification of high energy barriers as cause for it. Consequently, simple strategies to overcome these barriers are to increase simulation time (computationally expensive) or to use enhanced sampling techniques such as Hamiltonian replica exchange molecular dynamics and one-step perturbation. (C) 2016 The Authors. Journal of Computational Chemistry Published by Wiley Periodicals, Inc.
Year
DOI
Venue
2016
10.1002/jcc.24488
JOURNAL OF COMPUTATIONAL CHEMISTRY
Keywords
Field
DocType
free-energy calculations,one-step perturbation,replica exchange,thermodynamic integration,GROMOS
Hamiltonian (quantum mechanics),Alanine,Computational chemistry,Chemistry,Tripeptide,Sampling (statistics),Molecular dynamics,Dihedral angle,Thermodynamic integration,Side chain
Journal
Volume
Issue
ISSN
37
29
0192-8651
Citations 
PageRank 
References 
0
0.34
7
Authors
3
Name
Order
Citations
PageRank
Michael M. H. Graf141.21
Manuela Maurer200.68
Chris Oostenbrink329738.41