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The Best of Windows 95.com 1996 September
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RUNNING.IT
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1996-06-13
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General instructions for running ammp.
1) Ammp only understands ammp files. The functions involved in
taking a coordinate file and associating the atoms to the
potential functions is done by an auxilary program PREAMMP.
This separation allows the use of many potential functions without
the complete redesign of AMMP. We have used at least four, including
united atom AMBER potentials, UFF all-atom potentials, and two
reduced number of atoms model potentials for folding experiments.
The complexity of the code for potential generation is generally
quite high which makes these programs more difficult to support.
Hence it is a very good idea to keep them small and seperate which
makes support relatively easy.
2) running preammp. Preammp is the all-atom UFF potential
"compiler" which takes PDB files to AMMP files. It recognizes a
minimal subset of the PDB record set. Basically a card is an
ATOM card or it isn't. HETATM's should be recognized as well.
Preammp uses an atom dictionary to define atom types and a set
of templates to define bonds angles and the like. Two atom
dictionaries are included. atoms.new uses the UFF values for
charge generation (mompar and mom); atoms.adj uses values calibrated
against dipole moments of small molecules. Atoms.adj is probably
better. The templates are a set of files named by the same
three letter code used in the pdb file (i.e. ALA has a ala. template).
The template is a list of atoms and a list of bonds. Special
angles, torsion values, and hybrid terms may be included. Special
hybrids are included to enforce stereochemistry (the quick
way to get parameters for these is to use a hybrid of
"hybrid i j k l 0 0 ;" and analyze the hybrid after building a
non-specfic model. The height reported is then +- the height to use.)
preammp is (currently) a DOS program and should have a pif written for it
or run under a DOS window. If you modify dosprmpt.pif you can have a
window which works under windoz. (this is how i do it).
Prewin is the windows version of this and can be called directly from
AMMP.
examples
a) read in a protein
D:\ROB\PREAMMP>preammp
atom definition file:>
atoms.adj
Residue dictionary directory:>
protein
atom input coordinate file:>
dtx.pdb
AMMP file:>
dtx.amp
the directory .\protein\ (you only need the minimal specification)
contains the templates for ALA ... . The file dtx.pdb is scanned
and every time the residue number changes a new template is opened
and used. The output file "dtx.amp" will need to have the peptide
bonds pasted in and command examples are in the preammp\protein
directory. Atoms which are in the dictionary but not the
coordinates will be generated with a position of 0 0 0. You
will be warned about atoms, such as OXT, which are not in
the dictionary, but are in the coordinates.
b) do a new molecule "xyz"
D:\ROB\PREAMMP>preammp
atom definition file:>
atoms.adj
Residue dictionary directory:>
atom input coordinate file:>
AMMP file:>
xyz.amp
enter the dictionary name >
xyz
If there is no coordinate file or the coordinate file is empty the
program prompts for a dictionary name and the uses that to generate
a file with 0 0 0 for all atoms. Note that the template is in
the current directory.
3) Building coordinates.
initially you should freeze the positions of any defined atoms to
build the positions of the undefined (0 0 0 ) atoms. Use
nzinactive (or see what the menu command does). Then release all
the coordinates. Generally using gsdg to get a self-avoiding
start is a good idea.