[gmx-users] RE: Gibbs free energy of binding

[chris.neale at utoronto.ca]

Ehud,

when computing binding Delta Delta G between two close variants, why  
would entropy tend to cancel and enthalpy not tend to cancel? Even in  
the case of small perturbations, this sounds like wishful thinking to  
me ;)

Chris.

-- original message --

Hi Moshen,

I think everybody agrees that a full calculation such as Free Energy
Perturbation is the accurate, if difficult and lengthy, approach.
The entropic effects usually cannot simply be ignored. All I tried to
say was that there are approximation schemes for these (see the
reference below). Still, I would trust such approximations only when
computing binding Delta Delta G between two close variants (e.g. a wild
type protein and a one residue mutation) such that most entropic
contributions would tend to cancel.

Ehud.