Re: [AMBER] Modified force fields

From: Carlos Simmerling <carlos.simmerling.gmail.com>
Date: Mon, 9 Mar 2020 12:45:00 -0400

maybe you could tell us a little more about what you're trying to do. That
is a very old force field. Do you need that specific one, or do you want to
do similar work? You might take a look at this paper instead, it has the
same protein included but also many more, and is a modern force field and
solvent model that can be accessed in the standard Amber release.
https://pubs.acs.org/doi/abs/10.1021/ja5032776

--
Carlos Simmerling, Ph.D. (he, him, his)
Marsha Laufer Endowed Professor of Physical and Quantitative Biology
Professor, Department of Chemistry
Associate Director, Laufer Center for Physical and Quantitative Biology
Room 119 Laufer Center, Stony Brook University, Stony Brook, NY 11794-5115
http://www.simmerlinglab.org
On Mon, Mar 9, 2020 at 12:40 PM ankita mehta <mehtaroadies.gmail.com> wrote:
> Hiii,
> 1. I have run the above command . And i got the name.frcmod file.Which I am
> attaching here below.
> How to interpret this file so that i get to know parameters are taken from
> which file ?
>
> 2.I am attaching the pdf format of modified parameters file in this mail.
> I don't see any specification of angle and dihedral angle category.
> Can you guide me for the same.
> How to look for them?
>
> TIA!
>
>
>
> On Mon, Mar 9, 2020 at 3:53 AM Kellon Belfon <kellonbelfon.gmail.com>
> wrote:
>
> > 1. I think the order you have is correct. The parameters in your modified
> > leaprc (leaprc.ff101) should overwrite any similar definition in the
> ff99SB
> > leaprc, if it is loaded after the ff99SB leaprc. To double check if you
> > have the right parameters you can use parmed.
> >
> > parmed topology_file
> > writeFrcmod name.frcmod
> >
> > Then you can look at the name.frcmod file to see if it have the
> parameters
> > you intend to use.
> >
> > 2. The warning is letting you know that you did not define enough
> > parameters for an Improper dihedral. Which leads me to ask this question.
> > Which section of the file, loaded by loadAmberParams do you have the
> > definition for HW OW HW? Is it under IMPROPER or ANGLE? It should be
> under
> > the ANGLE section.
> >
> > On Sun, Mar 8, 2020 at 1:59 PM ankita mehta <mehtaroadies.gmail.com>
> > wrote:
> >
> > > Thanks for the reply .
> > > I managed to correct the formatting.
> > > Now, I am having following concerns.
> > > 1. I have two files from which parameters can be loaded .
> > > One is leaprc.ff99SB and other one is modified leaprc.ff101.
> > > Now, how to be sure that amber parameters of modified parameters will
> be
> > > loaded.
> > > Is there any connection  in what order i write them in tleap , that
> order
> > > it reads the parameters.
> > >
> > > 2. I am having some warning after loading the both parameters files:
> > > Improper torsion lines
> > > : what to do to correct this warning?
> > >
> > > Thanks!
> > >
> > >
> > >
> > > On Fri, Mar 6, 2020 at 6:30 PM David A Case <david.case.rutgers.edu>
> > > wrote:
> > >
> > > > On Fri, Mar 06, 2020, ankita mehta wrote:
> > > >
> > > > >I am just using the modified force field parameters .
> > > > >But it is giving me syntax error.
> > > > >Can anyone guide me for the same.
> > > >
> > > > Your "leaprc.ff100" is not a leaprc-like file that can be sourced
> from
> > > > the command line in tleap.  Instead, you need to use loadAmberParams
> to
> > > > load in a file like this.
> > > >
> > > > The file format info at http://ambermd.org/FileFormats.php#frcmod
> > > > indicates that these files are fixed format, with entries in
> particular
> > > > columns.  Your file is "free format", with just spaces between the
> > > > fields.  I'm not sure whether loadAmberParams will work on that or
> not.
> > > > Note that the supporting information file you used has the data
> > > > carefully laid out in particular columns.
> > > >
> > > > ....dac
> > > >
> > > >
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> >
> >
> > --
> > Kellon A. A. Belfon, Graduate Student
> > Carlos Simmerling Laboratory
> > The Laufer Center for Physical and Quantitative Biology
> > The Department of Chemistry, Stony Brook University
> > Stony Brook, New York 11794
> > Phone: (347) 546-4237 <(347)+546+4237>  Email:  kellon.belfon.stonybrook.
> > <kellon.belfon.stonybrook.edu>edu
> > _______________________________________________
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Received on Mon Mar 09 2020 - 10:00:02 PDT
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