Re: [AMBER] About the Mg charge in AMBER FF

From: FyD <>
Date: Fri, 04 Oct 2013 14:07:43 +0200

Dear George,

You might be interested in using R.E.D. Server at to derive atomic charges from
molecular electrostatic potential(s), and let the charge fitting step
decide what is the charge value for such a central Magnesium atom.

You can find examples of such an approach in R.E.DD.B. for iron complexes...
For instance see:

regards, Francois

> Sorry if this is trivial. Is there an issue with the +2 charge of Mg in
> AMBER FF or in other FFs? I mean, is there evidence from simulations that
> the use of +2 value will cause artifacts such as too strong interactions
> between Mg and negatively charged residues Asp, Glu?
> If this is the case would an ad hoc solution like the reduction of Mg
> charge to, say, +1.5 have any point?

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Received on Fri Oct 04 2013 - 05:30:04 PDT
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