As Thomas said, you should see the same PMF for both the forward and the
backward directions.
Note that there is a (generally small) difference between the binding
free energy and the difference between two points of the PMF curve.
Some authors (including me) consider that the delta(PMF) equals the
delta(G), but in principle, it's not totally true.
Best
Jerome
On Thu, 2010-05-20 at 14:27 +0800, Catein Catherine wrote:
> Dear Sir/Madam,
>
>
>
> I would like to determine the potential energy changes for drug binding the receptor and for the drug remove from the receptor. In practice, the PMF of binding should be lower than that of removing, otherwise no drug-receptor complex could be formed.
>
>
>
> I tried to use umbrella sampling method to determine the PMF as a function of distance between the drug and receptor. As the drug removal and drug binding process use the same path (defined as the distance between the drug and the receptor). I can only see PMF for binding and removal are the same.
>
>
>
> I noted that I can define steered MD by start and end point. Should I expect to see the PMF obtained by binding and removal of drugs are different using these two different SMD restraints?
>
>
>
> (1)
>
> # Change distance between atoms 485 and 134 from 15 A to 20 A
> &rst iat=485,134, r2=15., rk2 = 5000., r2a=20. /
>
>
> (2)
>
> # Change distance between atoms 485 and 134 from 20 A to 15 A
> &rst iat=485,134, r2=20., rk2 = 5000., r2a=15. /
>
> Please kindly help.
>
> Cat
>
>
>
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--
Jérôme Golebiowski, PhD (Hab. Dir. Rech.)
LCMBA, UMR CNRS-UNS 6001
Molecular Modeling team
University of Nice Sophia Antipolis, Parc Valrose
06108 Nice cedex 2
http://www.unice.fr/lcmba/golebiowski
tel +33 (0)4 92 07 61 03
fax +33 (0)4 92 07 61 25
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Received on Thu May 20 2010 - 01:30:07 PDT
