Title
Free enthalpies of replacing water molecules in protein binding pockets.
Abstract
Water molecules in the binding pocket of a protein and their role in ligand binding have increasingly raised interest in recent years. Displacement of such water molecules by ligand atoms can be either favourable or unfavourable for ligand binding depending on the change in free enthalpy. In this study, we investigate the displacement of water molecules by an apolar probe in the binding pocket of two proteins, cyclin-dependent kinase 2 and tRNA-guanine transglycosylase, using the method of enveloping distribution sampling (EDS) to obtain free enthalpy differences. In both cases, a ligand core is placed inside the respective pocket and the remaining water molecules are converted to apolar probes, both individually and in pairs. The free enthalpy difference between a water molecule and a CH(3) group at the same location in the pocket in comparison to their presence in bulk solution calculated from EDS molecular dynamics simulations corresponds to the binding free enthalpy of CH(3) at this location. From the free enthalpy difference and the enthalpy difference, the entropic contribution of the displacement can be obtained too. The overlay of the resulting occupancy volumes of the water molecules with crystal structures of analogous ligands shows qualitative correlation between experimentally measured inhibition constants and the calculated free enthalpy differences. Thus, such an EDS analysis of the water molecules in the binding pocket may give valuable insight for potency optimization in drug design.
Year
DOI
Venue
2012
10.1007/s10822-012-9620-8
Journal of computer-aided molecular design
Keywords
Field
DocType
Water sites,Binding pocket,Molecular dynamics,Free energy,Enveloping distribution sampling
Crystallography,Molecule,Ligand,Ligand (biochemistry),Computational chemistry,Chemistry,Atom,Crystal structure,Molecular dynamics,Gibbs free energy,Enthalpy
Journal
Volume
Issue
ISSN
26
12
1573-4951
Citations 
PageRank 
References 
3
0.42
10
Authors
6
Name
Order
Citations
PageRank
Sereina Riniker110710.39
Luzi J Barandun230.42
François Diederich3162.88
Oliver Krämer430.42
Andreas Steffen5235.81
Wilfred F. Van Gunsteren656484.80