Re: AMBER: to understand how frcmod.ff99SB works

From: Melinda Layten <mlayten.gmail.com>
Date: Thu, 28 Aug 2008 10:55:40 -0400

The dihedral calculation now uses 4 terms instead of the 2 used
previously. Since 1 and -2 are in both it replaces then extends.

Melinda Layten

On Thu, Aug 28, 2008 at 6:29 AM, Alan <alanwilter.gmail.com> wrote:
> Dears,
> So, I would like to understand what exactly is happening to parameters when
> you load from frcmod.ff99SB.
> So in tleap, loading leaprc.ff99SB, it will first load parm99.dat and then
> frcmod.ff99SB. Taking a set o parameter to illustrate, we have in
> parm99.dat, DIHE:
> C -N -CT-C 1 0.850 180.000 -2. C -N -CT-C 1 0.800 0.000 1.
> Looking at frcmod.ff99SB, we have:
> C -N -CT-C 1 0.00 0.0 -4. four amplitudes
> and
> C -N -CT-C 1 0.42 0.0 -3. phases for phi
> C -N -CT-C 1 0.27 0.0 -2.
> C -N -CT-C 1 0.00 0.0 1.
> So what exactly is happening here? Are those 4 new entries added to the 2
> first original or the simply replacing them?
> Many thanks in advance.
> Cheers,
> Alan
> --
> Alan Wilter S. da Silva, D.Sc. - CCPN Research Associate
> Department of Biochemistry, University of Cambridge.
> 80 Tennis Court Road, Cambridge CB2 1GA, UK.
>>>http://www.bio.cam.ac.uk/~awd28<<
>
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Received on Sun Aug 31 2008 - 06:07:33 PDT
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