Subject: Re: CCL: united atom force fields in Amber

From: David Case <[email-masked]>
Date: Fri, 12 Jan 2001 10:42:49 -0800

On Fri, Jan 12, 2001, David Case wrote:
> 
> > How to just add polar hydrogen (united atom) to residues, and how to 
> > assign the kollman united atom charges using AMBER6.0?
> 
> Run xleap -s (to ignore the default startup file), then type 
> "source leaprc.ff91".  This will load in the "parm91" (Weiner et al. united
> atom force field).  Because this force field is so old (developed in
> 1983-84) it is not used much anymore; be sure this is what you really want
> before spending a lot of time at it.  Amber6 is really designed with more
> recent force fields in mind.

.ooops...this answer was incorrect.  A more complex procedure is needed
to really get the original 1984 polar-hydrogen-only force field.  The
procedure mentioned above actually gets the all-atom 1986 force field.
(They are both called Weiner et al....)

My apologies for any confusion this has caused.

...dac

-- 

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David A. Case                     |  e-mail:      [email-masked]
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