Re: I need help with this

From: Chris Harrison (charris5_at_gmail.com)
Date: Fri Feb 11 2011 - 11:42:41 CST

Richard,

Create a psf/pdb set for each seperate molecular
system (moleculeA.psf, moleculeA.pdb, moleculeB.psf, etc),
then in VMD use a script similar to the following:

package require psfgen

psfcontext reset
resetpsf

topology top_all22_prot.inp

readpsf moleculeA.psf
coordpdb moleculeA.pdb

readpsf moleculeB.psf
coordpdb moleculeB.pdb

writepsf myNewSystem.psf
writepdb myNewSystem.pdb

Best,
Chris

--
Chris Harrison, Ph.D.
Theoretical and Computational Biophysics Group
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave., Urbana, IL 61801
char_at_ks.uiuc.edu                          Voice: 217-244-1733
http://www.ks.uiuc.edu/~char              Fax:   217-244-6078
Richard Wood <rwoodphd_at_yahoo.com> writes:
> Date: Wed, 9 Feb 2011 11:01:25 -0800 (PST)
> From: Richard Wood <rwoodphd_at_yahoo.com>
> To: namd-l_at_ks.uiuc.edu
> Subject: namd-l: I need help with this
> X-Mailer: YahooMailRC/555 YahooMailWebService/0.8.108.291010
> 
> Hi all,
> 
> I'm trying to set up a system where I have a lipid bilayer and I want to 
> "attach" a small molecule to the surface so I can run dynamics.
> 
> I have generated the bilayer using VMD and I have built the small molecule and 
> have parameters and a topology for it.  The problem I am having is in generating 
> the psf for the total system.
> 
> I have the *.pdb and *.psf for the bilayer and I can run that in namd; in fact, 
> I am minimizing it now as a test.  However, when I try to generate a psf file, 
> because the bilayer is numbered "funny", some residues have the same number and 
> don't get converted to the new file.  If I try to renumber everything by hand, 
> then it won't minimize (it gets to about 27 steps and then I get "weird numbers" 
> like -1.
> 
> I'm wondering if anyone has encountered this before and what the workaround is.
> 
> TIA,
> Richard
> 
> 
> 
>       

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