Re: [AMBER] Recurring problem: Ligand lose planarity

From: Jenny 148 <jenny.rs140.gmail.com>
Date: Sun, 26 Apr 2020 23:58:39 +0530

Thank you sir. I would do that.
On 26 Apr 2020 23:54, "Carlos Simmerling" <carlos.simmerling.gmail.com>
wrote:

> I think you should feel free to contact the corresponding author of any
> paper. They can't always help but it's probably the person with the most
> information.
>
> On Sun, Apr 26, 2020, 2:04 PM Jenny 148 <jenny.rs140.gmail.com> wrote:
>
> > Sir,
> > Would it be okay to contact them directly through mail with the query?
> > On 26 Apr 2020 22:54, "Carlos Simmerling" <carlos.simmerling.gmail.com>
> > wrote:
> >
> > > the Amber email help list is mostly questions about the software and
> how
> > to
> > > use it. For problems or questions about the force fields it might also
> be
> > > good to contact the authors of the force field you are using, since
> that
> > is
> > > often a different group that the people that usually answer things
> here.
> > > Sometimes people on the software list can answer force field questions,
> > but
> > > sometimes not...
> > >
> > >
> > > On Sun, Apr 26, 2020 at 12:34 PM Jenny 148 <jenny.rs140.gmail.com>
> > wrote:
> > >
> > > > Sir,
> > > > I have checked the atom types and they seemed fine. So I got all more
> > > > confused. In the mailing list, there were previous queries of the
> same
> > > kind
> > > > in the past, but could not see an exact response or noone shared how
> > they
> > > > dealt with it.
> > > > On 26 Apr 2020 21:20, "Carlos Simmerling" <
> carlos.simmerling.gmail.com
> > >
> > > > wrote:
> > > >
> > > > > I'm not a GAFF expert, so Junmei's input here would be great, but
> > what
> > > I
> > > > > would do would be to look at the atom type assignments, not just
> the
> > > > > parameters in the frcmod. Are the atoms that are becoming
> non-planar
> > > > > assigned atom types consistent with sp2 or sp3 geometries? Once the
> > > atom
> > > > > types are assigned then you end up with parameters, but maybe it's
> a
> > > > > chemical perception problem. I'd check that first.
> > > > >
> > > > > On Sun, Apr 26, 2020 at 11:34 AM Sruthi Sudhakar <
> > > > > sruthisudhakarraji.gmail.com> wrote:
> > > > >
> > > > > > Respected all,
> > > > > > Even I am facing the same issue using AMBER18 recently. The
> > > procedure I
> > > > > > followed is almost similar, but my ligand is combined to a
> > > > G-quadruplex
> > > > > > structure in tleap. But in frcmod file, even I am getting such
> high
> > > > > penalty
> > > > > > scores and my aromatic ligand also shows planarity distortion.
> Have
> > > > > > enquired regarding the same sometime back but did not get any
> > > response.
> > > > > > Hope this time someone might be able to give some insight on
> this.
> > > > > > Thank you
> > > > > >
> > > > > > On Sun, Apr 26, 2020 at 10:20 AM Jenny 148 <
> jenny.rs140.gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > > > Dear all,
> > > > > > > >The following is a recurring problem and I have repeated the
> > > > > simulation
> > > > > > > multiple times and still the issue persists. Please help.
> > > > > > > I have done a simulation on an aromatic ligand which must
> remain
> > > > > planar.
> > > > > > I
> > > > > > > optimized the structure in Gaussian, done docking on the
> ligand,
> > > > > > calculated
> > > > > > > ESP charges for selected conformers in Gaussian again. My
> ligand
> > > has
> > > > a
> > > > > +2
> > > > > > > charge. Then I have done the RESP fitting using antechamber and
> > > > > generated
> > > > > > > the frcmod file.(AMBER18)
> > > > > > > > antechamber -fi gout -i ligand.log -fo prepi -o ligand.prepi
> -c
> > > > resp
> > > > > > > > parmchk2 -i ligand.prepi -o ligand.frcmod -f prepi.
> > > > > > > >
> > > > > > > > Then I performed restrained minimization, heating and density
> > > > > > > equilibration and unrestrained equilibration and 500ns
> > production.
> > > My
> > > > > > > ligand strangely loses the planarity by the equilibration stage
> > and
> > > > > > shows a
> > > > > > > really distorted structure which is unacceptable. I have used
> the
> > > > gaff
> > > > > ff
> > > > > > > and Tip3p waterbox in the simulation. My frcmod file looks like
> > the
> > > > > > > following:
> > > > > > > > DIHE
> > > > > > > > ca-ca-cc-cc 4 2.800 180.000 2.000
> > same
> > > > as X
> > > > > > > -c2-ca-X , penalty score=232.0
> > > > > > > > ca-ca-cc-cf 4 2.800 180.000 2.000
> > same
> > > > as X
> > > > > > > -c2-ca-X , penalty score=232.0
> > > > > > > > ca-cc-cf-ha 4 16.000 180.000 2.000
> > same
> > > > as X
> > > > > > > -cc-cd-X , penalty score=136.0
> > > > > > > > ca-cc-cf-cf 4 16.000 180.000 2.000
> > same
> > > > as X
> > > > > > > -cc-cd-X , penalty score=136.0
> > > > > > > > cc-cc-cf-ha 4 16.000 180.000 2.000
> > same
> > > > as X
> > > > > > > -cc-cd-X , penalty score=136.0
> > > > > > > > cc-cc-cf-cf 4 16.000 180.000 2.000
> > same
> > > > as X
> > > > > > > -cc-cd-X , penalty score=136.0
> > > > > > > >
> > > > > > > > IMPROPER
> > > > > > > > c3-ca-na-cc 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > ca-ca-ca-na 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > ca-ca-ca-cc 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > ca-ca-ca-ha 1.1 180.0 2.0
> > Using
> > > > > > general
> > > > > > > improper torsional angle X- X-ca-ha, penalty score= 6.0)
> > > > > > > > cc-h4-cc-na 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > ca-cc-cc-cf 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > cc-cf-cf-ha 1.1 180.0 2.0
> > Same
> > > > as X
> > > > > > -X
> > > > > > > -ca-ha, penalty score= 46.8 (use general term))
> > > > > > > > c3-ca-na-cd 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > cc-h4-cd-na 1.1 180.0 2.0
> > Using
> > > > the
> > > > > > > default value
> > > > > > > > cc-cd-cc-ha 1.1 180.0 2.0
> > Same
> > > > as X
> > > > > > -X
> > > > > > > -ca-ha, penalty score= 38.9 (use general term))
> > > > > > > > Could someone suggest what might have went wrong and how to
> > solve
> > > > > this
> > > > > > > issue. I am attaching the image of my distorted ligand here.
> > > > > > > > My two major doubts are
> > > > > > > > 1. Is the frcmod file wrong?
> > > > > > > > 2. should I include the -nc flag in the resp fitting since my
> > > > ligand
> > > > > > has
> > > > > > > a +2 charge?
> > > > > > > When I repeated the procedure to an old ligand which we had
> then
> > > > > > simulated
> > > > > > > in AMBER14, the newly generated frcmod files have same
> components
> > > as
> > > > > the
> > > > > > > old files,but with a high penalty score. Is there something
> > > peculiar
> > > > we
> > > > > > > should mention in the latest version?
> > > > > > > > Thanks in advance
> > > > > > > >
> > > > > > > > --
> > > > > > > > Jenny R.S
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Received on Sun Apr 26 2020 - 11:30:03 PDT
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