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

[mohsen ramezanpour]

Ok.you are right,actually entropy has contribution as H,of course it seems
to me!

On Sun, Oct 24, 2010 at 9:32 PM, <chris.neale at utoronto.ca> wrote:

> Mohsen,
>
> Writing H as E+PV does not change the nature of my question. It was said
> that when computing binding Delta Delta G between two close variants, most
> entropic contributions would tend to cancel. My question is why, when there
> are many components to the gibbs free energy, would some components (stated
> as entropy) cancel in a delta delta G while some are not expected to cancel
> (implicitly taken to be enthalpy or internal energy or pressure volume
> work). And also, is this a hunch or has it been shown?
>
> Thanks,
> Chris.
>
>
> -- original message --
>
> Dear Chris
> Do you mean Gibbs free energy?
> there are a general relation in statistical mechanics as below:
> G=E-TS+PV
> in this relation E is internal energy and S is entropy,then enthalepy is
> not
> comming in relation anywhere,
> besides there are not any reason for canceling G when Del Del S is canceled
>
> On Sun, Oct 24, 2010 at 9:04 PM, <chris.neale at utoronto.ca> wrote:
>
>  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 -
>>
>
>
> --
> gmx-users mailing list    gmx-users at gromacs.org
> http://lists.gromacs.org/mailman/listinfo/gmx-users
> Please search the archive at
> http://www.gromacs.org/Support/Mailing_Lists/Search before posting!
> Please don't post (un)subscribe requests to the list. Use thewww interface
> or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/Support/Mailing_Lists
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20101024/3ffbdc41/attachment.html>