Re: [AMBER] Setup of defined salt concentrations

From: InSuk Joung <>
Date: Tue, 20 Apr 2010 10:44:24 -0400

If you think the ions are not distributed uniformly, you can use the ptraj
command, 'randomizeions'. Please refer to AmberTools manual.
By the way, why do you think the distribution is dependent on your system?
I believe Leap should not give different results depending on systems.

On Tue, Apr 20, 2010 at 9:16 AM, Anselm Horn <> wrote:

> Dear all,
> (I apologize if this question has been asked and answered before)
> is there a canonical way in the Amber community to add ions (e.g. Na+
> and Cl-) not for charge neutralization of the protein system, but to
> create a given (e.g. physiological) salt concentration in the solution?
> In the Amber mail archives I found a perl script from Thomas Cheatham
> that computes the number of necessary molecules from a given volume.
> Of course, these ions can then be added with leap.
> However, when I tried it once for a single system, all ions appeared
> rather crowded and were not distributed in an approximately uniform way
> in the solvent box; this could have been an outcome of my system, of
> course.
> So my question is: How do other people deal with this?
> Thanks in advance for your advice.
> Regards,
> Anselm
> Bioinformatik
> Friedrich-Alexander-Universität Erlangen-Nürnberg
> Germany
> _______________________________________________
> AMBER mailing list

InSuk Joung
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Received on Tue Apr 20 2010 - 08:00:02 PDT
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