From: Wanzhi Qiu (wanzhiqiu128_at_yahoo.com)
Date: Wed Feb 15 2012 - 20:50:30 CST
I have two structures each with psf/pdb files and would like to combine them into one single structure.
The graphene psf/pdb fiels are generated as outlined in my previous email. The other pair of psf/pdb didn't show any problem here. The psfgen is not directly called in my combining process, but in-directly in the script I used for the combining. The complete script (combine.tcl) is list below:
set psf0 graphene.psf
set pdb0 graphene.pdb
set psf1 other.psf
set pdb1 other.pdb
set finalPsf c.psf
set finalPdb c.pdb
# Load the topology and coordinates.
package require psfgen
# Write the combination.
When issuing "source combine.tcl" in the Tkconsole, produces following:
psfgen) clearing structure, preserving topology and aliases
psfgen) reading structure from psf file graphene.psf
psfgen) error reading atoms
MOLECULE DESTROYED BY FATAL ERROR! Use resetpsf to start over.
Follow-on trials reveal that commands "readpsf graphene.psf" and "coordpdb graphene.pdb" in the Tkconsole both fail. BTW, I guess the default topology file top_all27_prot_lipid.inp is involved here, don't know whether this is right or how to check which topology file is actually used.
From: Axel Kohlmeyer <akohlmey_at_gmail.com>
To: Wanzhi Qiu <wanzhiqiu128_at_yahoo.com>
Cc: Cruz-Chu Eduardo Roberto <eduardo.cruz_at_mavt.ethz.ch>; "namd-l_at_ks.uiuc.edu" <namd-l_at_ks.uiuc.edu>
Sent: Thursday, 16 February 2012 1:13 PM
Subject: Re: namd-l: Graphene pdb/psf files cannot be read by psfgen
On Wed, Feb 15, 2012 at 9:06 PM, Wanzhi Qiu <wanzhiqiu128_at_yahoo.com> wrote:
> Hi Eduardo and All,
> Thanks for your reply. Yes you are right psf should be read before reading
> pdb. Unfortunately this doesn't solve the problem. Same error messages are
> still returned when issuing readpsf/coordpdb commands from Tkconsole. The
> psf/psb files have no problem in being loaded to VMD via "mol load" command.
> I guess there might be some formatting issues in the psf/pdb files generated
> this way - starting with the Carbon Nanostructure Builder, then select all,
> then issue "$all writepdb/psf" commands.
> Could you please enlighten me on what might be wrong here.
you have to differentiate between input for psfgen
and regular VMD. the do maintain two different
"states". please provide the *complete* list of
commands for psfgen and a description of what
it is that you overall want to do with this.
it is often difficult to debug these things without context.
> Kind regards,
> From: Cruz-Chu Eduardo Roberto <eduardo.cruz_at_mavt.ethz.ch>
> To: Wanzhi Qiu <wanzhiqiu128_at_yahoo.com>
> Cc: "namd-l_at_ks.uiuc.edu" <namd-l_at_ks.uiuc.edu>
> Sent: Wednesday, 15 February 2012 10:06 PM
> Subject: Re: namd-l: Graphene pdb/psf files cannot be read by psfgen
> readpsf command must go before coordpdb; that is:
> readpsf graphene.psf
> coordpdb graphene.pdb
> then you add other molecules
> readpsf smth.psf
> coordpdb smth.pdb
> and output the final structure
> writepsf final.psf
> writepdb final.pdb
> a more detailed explanation is provided in the psfgen user guide, available
> in the website.
> On Feb 15, 2012, at 8:14 AM, Wanzhi Qiu wrote:
> Dear NAMDers,
> I constructed a small graphene sheet using VMD Carbon Nanostructure Builder
> with options of Bonds, Angles etc are ticked. The result is shown on VMD
> OpenGL window and pdb/psf files are then generated using writepdb/writepsf
> commands in Tk console. The files appear to be correct with numbers for
> bonds, angles etc in the psf file. However, they fail when I try to combine
> the graphene with other molecules.
> The problem is that the generated graphene.pdb/graphene.psf cannot be read
> by psfgen. In particular, the commands issued in the Tk console and error
> messages are:
> gives following result:
> psfgen) reading coordinates from pdb file graphene.pdb
> psfgen) no segment
> psfgen) Warning: failed to set coordinate for atom C GRA:1
> (patten repeat for all atoms)
> gives following result:
> psfgen) reading structure from psf file graphene.psf
> psfgen) error reading atoms
> MOLECULE DESTROYED BY FATAL ERROR! Use resetpsf to start over.
> I suspect that the problem might be related to the residue name "GRA" in the
> pdb file. The first 3 lines of the pdb file are:
> CRYST1 8.508 7.368 100.000 90.00 90.00 90.00 P 1 1
> ATOM 1 C GRA X 1 0.000 0.000 0.000 0.00 0.00 C
> ATOM 2 C GRA X 2 -0.709 1.228 0.000 0.00 0.00 C
> Please let me know if you have any advices/comments/suggestions.
> Many thanks,
> Wanzhi Qiu, Ph. D.
> Senior Researcher
> National ICT Australia
> Department of Electrical & Electronic Engineering
> The University of Melbourne Parkville, Victoria 3010 Australia
Dr. Axel Kohlmeyer
College of Science and Technology
Temple University, Philadelphia PA, USA.
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