Edmund,

        No, this kind of technical information isn't documented...

        If I recall correctly, when PyMOL hooks fragments together, it
replaces hydrogen with a bond along the existing vectors.  In other
words, one fragment is translated so as to fit onto another.

        Peptides are a special case because the phi-psi vectors are
fairly well defined.  Nevertheless, I wouldn't trust peptide geometries
generated by PyMOL until they've passed through some external
force-field, such as MMFF or Amber/OPLS.  

        PyMOL is a reasonable builder for defining the covalent scaffold
of peptides and arbitrary small molecules, but it knows nothing about
forces and energies.  

Cheers,
Warren

--
mailto:war...@delanoscientific.com
Warren L. DeLano, Ph.D.
Principal Scientist
DeLano Scientific LLC
Voice (650)-346-1154 
Fax   (650)-593-4020

> -----Original Message-----
> From: pymol-users-ad...@lists.sourceforge.net [mailto:pymol-users-
> ad...@lists.sourceforge.net] On Behalf Of Edmund Kump
> Sent: Thursday, September 18, 2003 8:59 PM
> To: pymol-users@lists.sourceforge.net
> Subject: RE: [PyMOL] modifying atom coordinates
> 
> Yes, but what happens when, for example, I take a lysine residue, and
> connect a glutamine residue? Shouldn't all the atoms have different
> coordinates from when they are stand alone, based on the forces from
> nearby atoms? Does pymol account for this as residues are added, or is
> there a command or wizard which accounts for nearby atomic forces that
I
> would execute after I build my chain?
> 
> To give some background to what I'm trying to do, the end goal of my
> project is to modify the forces involved in protien folding. I'm sorry
if
> I'm asking questions that are documented, but I haven't seen anything
that
> answers my question yet.
> 
> Much Thanks,
> Edmund
> 
> 
>  On Wed, 17 Sep 2003, Warren L. DeLano wrote:
> 
> > Hi Edmund,
> >
> >     Actually, PyMOL uses a set of stored coordinates for fragments
> > and residues.  They can be found in
$PYMOL_PATH/data/chempy/fragments.
> > The files have .pkl extensions, which stands for pickled chempy
model.
> > These files can be viewed directly in PyMOL, or can be introspected
by
> > unpickling them in a Python interpreter.
> >
> > Cheers,
> > Warren
> >
> > --
> > mailto:war...@delanoscientific.com
> > Warren L. DeLano, Ph.D.
> > Principal Scientist
> > DeLano Scientific LLC
> > Voice (650)-346-1154
> > Fax   (650)-593-4020
> >
> > > -----Original Message-----
> > > From: pymol-users-ad...@lists.sourceforge.net [mailto:pymol-users-
> > > ad...@lists.sourceforge.net] On Behalf Of Edmund Kump
> > > Sent: Wednesday, September 17, 2003 3:49 AM
> > > To: pymol-users@lists.sourceforge.net
> > > Subject: [PyMOL] modifying atom coordinates
> > >
> > > Greetings,
> > >
> > > I am interested in modifying how pymol generates the coordinates
of
> > > atoms in a peptide chain as you add residues to it. I am an
> > > undergraduate math student, so my knowledge in this area is in the
> > > range of "nothing".  I would assume that this would be in the
bonding
> > > or editor modules, but so far I haven't found what I'm looking
for. In
> > > what Chempy or Pymol module(s) can I find the code that determines
> > > these coordinates?
> > >
> > > Thanks,
> > > Edmund Kump
> > > ek...@mathlab.sunysb.edu
> > > Applied Mathematics and Statistics
> > > SUNY Stony Brook
> > >
> > >
> > >
> > > -------------------------------------------------------
> > > This sf.net email is sponsored by:ThinkGeek
> > > Welcome to geek heaven.
> > > http://thinkgeek.com/sf
> > > _______________________________________________
> > > PyMOL-users mailing list
> > > PyMOL-users@lists.sourceforge.net
> > > https://lists.sourceforge.net/lists/listinfo/pymol-users
> >
> >
> 
> 
> 
> -------------------------------------------------------
> This sf.net email is sponsored by:ThinkGeek
> Welcome to geek heaven.
> http://thinkgeek.com/sf
> _______________________________________________
> PyMOL-users mailing list
> PyMOL-users@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/pymol-users



Reply via email to