[gmx-users] -vsite hydrogen

2014-12-29 Thread h . alizadeh
Dear Users,
I am simulating a membrane protein with charmm ff with a 2fs time step.
How the results will be affected if I use a 5fs time step by using -vsite
hydrogen option in pdb2gmx? Do my results loose their accuracy if I use
this option?
Best wishes,
H.A

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Re: [gmx-users] -vsite hydrogen

2014-12-29 Thread Justin Lemkul



On 12/29/14 6:28 AM, h.aliza...@znu.ac.ir wrote:

Dear Users,
I am simulating a membrane protein with charmm ff with a 2fs time step.
How the results will be affected if I use a 5fs time step by using -vsite
hydrogen option in pdb2gmx? Do my results loose their accuracy if I use
this option?


Well, it's easy to test.  The membrane properties that are expected to be 
observed are very easy to quantify.  We didn't test our CHARMM36 port with 
virtual sites at all, so we cannot recommend such usage.  Test thoroughly before 
doing any real production work.  Membranes are extremely sensitive to alteration.


-Justin

--
==

Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalem...@outerbanks.umaryland.edu | (410) 706-7441
http://mackerell.umaryland.edu/~jalemkul

==
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Re: [gmx-users] -vsite hydrogen

2014-12-29 Thread Wojciech Kopeć
We have tested virtual sites with CHARMM36 lipids; straightforward usage
gives too ordered membranes. We have created custom virtual sites
construction for lipid hydrogens and used them for pure membranes as well
as for membrane proteins, and the differences between membrane properties
with virtual sites and without are usually minor (but still noticeable).
The parameters can be found here http://memphys.dk/node/71 and the paper
http://pubs.acs.org/doi/abs/10.1021/ct500100f

Wojciech




Message: 1
Date: Mon, 29 Dec 2014 10:27:47 -0500
From: Justin Lemkul jalem...@vt.edu
To: gmx-us...@gromacs.org
Subject: Re: [gmx-users] -vsite hydrogen
Message-ID: 54a172f3.5040...@vt.edu
Content-Type: text/plain; charset=windows-1252; format=flowed



On 12/29/14 6:28 AM, h.aliza...@znu.ac.ir wrote:
 Dear Users,
 I am simulating a membrane protein with charmm ff with a 2fs time step.
 How the results will be affected if I use a 5fs time step by using -vsite
 hydrogen option in pdb2gmx? Do my results loose their accuracy if I use
 this option?

Well, it's easy to test.  The membrane properties that are expected to be
observed are very easy to quantify.  We didn't test our CHARMM36 port with
virtual sites at all, so we cannot recommend such usage.  Test thoroughly
before
doing any real production work.  Membranes are extremely sensitive to
alteration.

-Justin

On Mon, Dec 29, 2014 at 8:52 PM, 
gromacs.org_gmx-users-requ...@maillist.sys.kth.se wrote:

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 Today's Topics:

1. Re: -vsite hydrogen (Justin Lemkul)
2. Re: Obtaining PMF for change in domain position (Justin Lemkul)
3. pdb information (elham tazikeh)
4. Re: pdb information (Justin Lemkul)
5. Re: Obtaining PMF for change in domain position (Abhi Acharya)
6. Gromacs error regarding default gromos bond type and  angle
   type (Negar Parvizi)


 --

 Message: 1
 Date: Mon, 29 Dec 2014 10:27:47 -0500
 From: Justin Lemkul jalem...@vt.edu
 To: gmx-us...@gromacs.org
 Subject: Re: [gmx-users] -vsite hydrogen
 Message-ID: 54a172f3.5040...@vt.edu
 Content-Type: text/plain; charset=windows-1252; format=flowed



 On 12/29/14 6:28 AM, h.aliza...@znu.ac.ir wrote:
  Dear Users,
  I am simulating a membrane protein with charmm ff with a 2fs time step.
  How the results will be affected if I use a 5fs time step by using
 -vsite
  hydrogen option in pdb2gmx? Do my results loose their accuracy if I use
  this option?

 Well, it's easy to test.  The membrane properties that are expected to be
 observed are very easy to quantify.  We didn't test our CHARMM36 port with
 virtual sites at all, so we cannot recommend such usage.  Test thoroughly
 before
 doing any real production work.  Membranes are extremely sensitive to
 alteration.

 -Justin

 --
 ==

 Justin A. Lemkul, Ph.D.
 Ruth L. Kirschstein NRSA Postdoctoral Fellow

 Department of Pharmaceutical Sciences
 School of Pharmacy
 Health Sciences Facility II, Room 629
 University of Maryland, Baltimore
 20 Penn St.
 Baltimore, MD 21201

 jalem...@outerbanks.umaryland.edu | (410) 706-7441
 http://mackerell.umaryland.edu/~jalemkul

 ==


 --

 Message: 2
 Date: Mon, 29 Dec 2014 10:29:18 -0500
 From: Justin Lemkul jalem...@vt.edu
 To: gmx-us...@gromacs.org
 Subject: Re: [gmx-users] Obtaining PMF for change in domain position
 Message-ID: 54a1734e.5000...@vt.edu
 Content-Type: text/plain; charset=windows-1252; format=flowed



 On 12/29/14 6:57 AM, Abhi Acharya wrote:
  Hello GROMACS Users,
 
  This is a problem I am facing for the first time. Kindly guide be to the
  best options.
 
  I have a protein which has two large domains connected by a flexible
 linker
  peptide (~10 aa). The two domains seem to interact with each other and
 have
  been crystallized in three different conformations. I want to calculate
 the
  change in binding energy of the two domains wrt change in their relative
  position, i.e. keeping position of one domain constant what is change in
  binding energy as the other domain moves from conformation 1, through
  conformation 2 to finally, conformation 3. What is the best way to do so?
 

 You need to describe what these three conformations are.  Do they involve
 rotations of the domains with respect to one another