Re: [gmx-users] Dynamics cross correlation map

2010-03-24 Thread Ran Friedman, Biochemisches Inst.

Hi Sukesh,

I once put a version of g_covar that can calculate the correlations in the 
user contributions. Check if it's there or reply to me privately if you 
can't find it (though I'm on the road till Friday).


Good luck,
Ran

On Wed, 24 Mar 2010 11:46:42 +0530
 sukesh chandra gain suk...@atc.tcs.com wrote:

Hi Tsjerk,

Thank you for your reply. May be I was not very clear with my previous 
post.
I am not looking for covariance / atomic covariances map (ie., 
covar.xpm/covara.xpm) which are generated by g_covar tool in GROMACS. I am 
particularly trying to get correlation map (example: 
http://www.pnas.org/content/102/4/994/F2.large.jpg, 
http://www.pnas.org/content/99/26/16597/F3.small.gif). I hope there is a 
difference between covariance matrix and correlation matrix.
The correlated motions between two atoms is calculated as the magnitude of 
the co-relation coefficient between the atoms.  In case of a system it can 
be assessed by examining the magnitude of all pairwise cross-correlation 
coefficients. The cross-correlation coefficient, C(i,j) for each pair of 
atoms i and j is calculated as:
C(i,j) =  delta r(i) * delta r(j)  / sqrt  sqr(delta r(i) )  . sqrt  
sqr(delta r(j) )  , where delta r(i) is the displacement from mean 
position of the ith atom and   symbol represents the time average.
This function returns a matrix of all atom-wise cross-correlations whose 
elements, C(i,j), may be displayed in a graphical representation frequently 
termed a dynamical cross-correlation map, or DCCM. If C(i,j) = 1 the 
fluctuations of atoms i and j are completely correlated, if C(i,j) = -1 the 
fluctuations of atoms i and j are completely anticorrelated and if C(i,j) = 
0 the fluctuations of i and j are not correlated.
Now my query is there any tool like g_correlation 
(http://www.mpibpc.mpg.de/home/grubmueller/projects/MethodAdvancements/GeneralizedCorrelations/index.html) 
by which I can get the cross-correlation matrix from covariance matrix or 
directly from trajectory file.


Ref:1. Hünenberger PH, Mark AE, van Gunsteren WF; Fluctuation and 
cross-correlation analysis of protein motions observed in nanosecond 
molecular dynamics simulations; JMB 1995; 252:492-503
2. Oliver F. Lange, H. Grubmüller; Generalized Correlation for 
Biomolecular Dynamics; Proteins  2006; 62:1053-1061



Thank You,
Regards,
Sukesh

--
Sukesh Chandra Gain
TCS Innovation Labs
Tata Consultancy Services Ltd.
'Deccan Park', Madhapur
Hyderabad 500081
Phone:  +91 40 6667 3572

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--
Ran Friedman
Postdoctoral Fellow
Computational Structural Biology Group (A. Caflisch)
Institute of Biochemistry
University of Zurich
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
Tel. +41-44-639
Skype: ran.friedman
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Re: [gmx-users] Assembling a good simulation starting point

2010-02-19 Thread Ran Friedman, Biochemisches Inst.

Hello John,

How large was the force after EM? Large forces often results in systems that 
explode during the simulation. Also, did you minimise with or without 
solvent? You assessment seems correct - the initial structure wasn't 
minimised and the tools of the trade are trying different conformations, 
minimising in vacuo at first and using other modelling tools before Gromacs. 
Also, read a bit in the mailing list and search the literature for similar 
studies.


Good luck,
Ran

On Thu, 18 Feb 2010 19:08:11 -0800 (PST)
 John Ladasky blind.watchma...@yahoo.com wrote:

Hello everyone,

I'm a fairly new GROMACS user.  I'm running GROMACS 4.0.5 on top of Ubuntu 
Linux 9.10.  I am still learning a lot.

 
I just tried to set up my first fairly complex simulation, and it failed.  
I have a protein of interest, a beta barrel with a hydrophobic, 
ligand-binding interior.  I am interested in making mutations to this 
protein, with the goal of getting it to bind to a rather different ligand 
than the one it normally binds.

 
The way that I propose to go about studying this problem is to construct a 
partially-unfolded version of the protein structure, add my ligand of 
interest, and then run an energy minimization.

 
My first naive attempt to construct the partially-unfolded protein was not 
successful.  I knew that it might have problems, but I tried it anyway.  
Using Biopython, I rotated the atomic coordinates so that the beta barrel 
was parallel to an axis.  Then I simply pulled all of the atoms 3 Angstroms 
away from the axis.  Finally, I inserted my ligand.  Visually, inspecting 
the starting structure with PyMol, I didn't see anything egregious.  
However, I could have some unwanted close contacts.


I got a few long bond warnings from pdb2gmx, but I persisted.  I got 
through genbox, editconf, and my first grompp sucessfully. But then when I 
tried the first, position-restrained energy minimization, it aborted with 
too many LINCS warnings.   I blew the system up.


These LINCS warnings could come from close contacts, or from large forces 
in over-stretched bonds which resulted from my crude approach to expanding 
the protein structure.  Whatever the cause, I need a smarter way to start.  
I am open to ANY suggestions!

 
What I THINK I might want to do is to manipulate the starting structure in 
a more natural way.  For example, selecting some peptide bonds in the beta 
turns, and changing their angles.  A program which allows me to manipulate 
structures, and not just simulate natural forces, is what I think I need.  
 
Surely, people who have used GROMACS will have faced problems simliar to 
mine.  Thanks for your advice!

 
John Ladasky




 


--
Ran Friedman
Postdoctoral Fellow
Computational Structural Biology Group (A. Caflisch)
Institute of Biochemistry
University of Zurich
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
Tel. +41-44-639
Skype: ran.friedman
--

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Re: [gmx-users] HF/6-31G** ESP derived charges to replace PRODRG assigned ones

2009-04-19 Thread Ran Friedman, Biochemisches Inst.

Dear Josmar,

As for the GROMOS FF, I've included a link to the paper describing the most 
recent (AFAIK) version of the FF in one of the recent mailing list massages.


Good luck,
Ran

On Sat, 18 Apr 2009 15:56:11 -0400
 Justin A. Lemkul jalem...@vt.edu wrote:



Josmar R. da Rocha wrote:

Dear Ran,

Thanks for answering and sorry to take so long to reply. After your 
response I went seach for more information about that. What I read here 
in the list is that some people uses antechamber to generate am1-bcc 
charges (or RESP charges using Gaussian program) and convert the output 
files to a .top file (using the amb2gmx.pl script) that can be used in 
gromacs, however, nobody says the kind of ff they intend to use that 
charges with. Do these type of charges can also be used with Gromos96 ff 
( 43a1)? Thanks in advance!




The amb2gmx was created to handle AMBER-to-GROMACS conversion.  It is 
unlikely that it would be useful for ffG43a1.  Since 43a1 is a united-atom 
force field, you have to compensate for the fact that nonpolar hydrogen 
atoms are absent. Furthermore, quantum charge calculation is not a 
necessary component of Gromos96 parameter derivation.  See, for example:


http://wiki.gromacs.org/index.php/Parameterization

-Justin


Regards,

Josmar Rocha

 

--- Em *sex, 27/3/09, Ran Friedman, Biochemisches Inst. 
/r.fried...@bioc.uzh.ch/* escreveu:


De: Ran Friedman, Biochemisches Inst. r.fried...@bioc.uzh.ch
Assunto: Re: [gmx-users] HF/6-31G** ESP derived charges to replace
PRODRG assigned ones
Para: bije...@yahoo.com.br, Discussion list for GROMACS users
gmx-users@gromacs.org
Data: Sexta-feira, 27 de Março de 2009, 17:35

Dear Josmar,

You haven't written which force field you plan to use. For OPLS and 
AMBER
QM-based optimisation should be fine. In Gromos, the FF was developed 
with the
aim of reproducing experimental results and I'm not sure if you can 
find a
better solution than examining other residues with the same chemical 
moieties or
use the same approach as reported in the relevant manuscripts. Some 
software
packages can also be used - these are mostly proprietary and not so 
easy to use.


Once you derive the parameters, it's a good idea to make some test 
runs of
the ligands and see if they behave as expected before you actually run 
a

simulation with the
 protein. For example, if a conjugate ring system isn't
planar something may be wrong in the setting.

There's no easy solution - this is why it's considered an advanced
topic. It is, however, very important. I've encountered a ligand that 
leaves
its binding site during a simulation due to wrong parameters (in this 
case, the
protonation of a protein side chain - FEBS  581, Pages 4120-4124, 
2007).


Hope that helped,
Ran

On Fri, 27 Mar 2009 12:22:01 -0700 (PDT)
 Josmar R. da Rocha bije...@yahoo.com.br wrote:
 Dear users,
 
 I have been reading some posts about using externally computed 
charges to
replace Prodrg charges at ligand topology files. Many users commented 
on the low

trustability given to Prodrg charges (e.g
http://www.mail-archive.com/gmx-users@gromacs.org/msg02360.html ;
http://www.mail-archive.com/gmx-users@gromacs.org/msg17351.html ). Dr. 
Verli

pointed out the
 use of semi-empirical methods such as RM1 in cases not involving
simulations with sulphate or phosphate groups (what is not my case) 
and the use
of QM methods with the 6-31G** basis set, for example, to obtain 
robust charges
(http://www.mail-archive.com/gmx-users@gromacs.org/msg03410.html). On 
the other
hand Dr. Mobley defined as a a bad idea to compute charges for an 
all-atom
case using QM and then try to convert these to a united atom force 
field.
Other users advice that the best charges are that compatible with the 
force

field parametrization
 (http://www.mail-archive.com/gmx-users@gromacs.org/msg10760.html ;
http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html), 
usually
pointing to http://wiki.gromacs.org/index.php/Parameterization. Dr 
Friedman
suggested that to calculate the electrostatic potential over the 
whole
molecule, and fit the atomic charges so that they reproduce this 
potential

in
 order to make it less sensitive to small changes in the geometry of 
the

molecule may give good results
(http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html). Dr. 
Lemkul
stressed the need for charges refinement to reproduce 
experimentally-observed

behavior while trying to use QM charges with Gromos ff. since
Parameterization under Gromos usually involves empirical derivation 
of

physical parameters, and free energy calculations using thermodynamic
integration. Few examples of protein-ligand studies using Gromacs and
Gromos96 ff that I have access (from literature) seem to treat it as 
take

Re: [gmx-users] HF/6-31G** ESP derived charges to replace PRODRG assigned ones

2009-04-01 Thread Ran Friedman, Biochemisches Inst.

Hi,

I've recently used OPLS-AA for a similar calculation. It has the advantage 
that many atom types are already defined in Gromacs and that QM-based 
calculations give you reasonable charges.


Note that it may take considerable simulation time (tens of ns) to 
discriminate between similar docked poses of the same molecule, though MD 
can give you a hint. If things were easier docking programs would do a 
better job.


Ran.

On Wed, 01 Apr 2009 00:12:31 -0600
 Lucio Ricardo Montero Valenzuela lucio...@ibt.unam.mx wrote:

So it 's better to switch to the OPLS forcefield if I want to compute the
charges?.
How can I implement the OPLS-UA if my gromacs (version 3.3) only includes 
the

OPLS-AA?
Mensaje citado por Justin A. Lemkul jalem...@vt.edu:




Lucio Montero wrote:
 How about MOPAC to calculate the charges for 3-methyladenine (this
 molecule has a charge +1) for using the G43a1 force field?.



That may not be a bad place to start, but any parameters applied to a 
Gromos

molecule have to reproduce condensed phase thermodynamic observables.
Empirical
fitting of the initial parameters may be required.  Refer to the primary
literature.  The reference for the 53a5 and 53a6 parameter sets are 
published

in
JCC, which may provide you with some useful information.

-Justin

 --
 From: Ran Friedman, Biochemisches Inst. r.fried...@bioc.uzh.ch
 Sent: Friday, March 27, 2009 2:35 PM
 To: bije...@yahoo.com.br; Discussion list for GROMACS users
 gmx-users@gromacs.org
 Subject: Re: [gmx-users] HF/6-31G** ESP derived charges to replace
 PRODRGassignedones

 Dear Josmar,

 You haven't written which force field you plan to use. For OPLS and
 AMBER QM-based optimisation should be fine. In Gromos, the FF was
 developed with the aim of reproducing experimental results and I'm not
 sure if you can find a better solution than examining other residues
 with the same chemical moieties or use the same approach as reported
 in the relevant manuscripts. Some software packages can also be used -
 these are mostly proprietary and not so easy to use.

 Once you derive the parameters, it's a good idea to make some test
 runs of the ligands and see if they behave as expected before you
 actually run a simulation with the protein. For example, if a
 conjugate ring system isn't planar something may be wrong in the 
setting.


 There's no easy solution - this is why it's considered an advanced
 topic. It is, however, very important. I've encountered a ligand that
 leaves its binding site during a simulation due to wrong parameters
 (in this case, the protonation of a protein side chain - FEBS  581,
 Pages 4120-4124, 2007).

 Hope that helped,
 Ran

 On Fri, 27 Mar 2009 12:22:01 -0700 (PDT)
  Josmar R. da Rocha bije...@yahoo.com.br wrote:
 Dear users,

 I have been reading some posts about using externally computed
 charges to replace Prodrg charges at ligand topology files. Many
 users commented on the low trustability given to Prodrg charges (e.g
 http://www.mail-archive.com/gmx-users@gromacs.org/msg02360.html ;
 http://www.mail-archive.com/gmx-users@gromacs.org/msg17351.html ).
 Dr. Verli pointed out the use of semi-empirical methods such as RM1
 in cases not involving simulations with sulphate or phosphate groups
 (what is not my case) and the use of QM methods with the 6-31G**
 basis set, for example, to obtain robust charges
 (http://www.mail-archive.com/gmx-users@gromacs.org/msg03410.html). On
 the other hand Dr. Mobley defined as a a bad idea to compute charges
 for an all-atom case using QM and then try to convert these to a
 united atom force field. Other users advice that the best charges
 are that compatible with the force field parametrization
 (http://www.mail-archive.com/gmx-users@gromacs.org/msg10760.html ;
 http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html),
 usually pointing to
 http://wiki.gromacs.org/index.php/Parameterization. Dr Friedman
 suggested that to calculate the electrostatic potential over the
 whole molecule, and fit the atomic charges so that they reproduce
 this potential in order to make it less sensitive to small changes
 in the geometry of the molecule may give good results
 (http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html).
 Dr. Lemkul stressed the need for charges refinement to reproduce
 experimentally-observed behavior while trying to use QM charges with
 Gromos ff. since Parameterization under Gromos usually involves
 empirical derivation of physical parameters, and free energy
 calculations using thermodynamic integration. Few examples of
 protein-ligand studies using Gromacs and Gromos96 ff that I have
 access (from literature) seem to treat it as take it for granted
 issue (any reference with a more detailed description would be
 welcome :-)). Despite reading on this topic I could not compile all
 the information in a clear and objective way (may be because I'm in
 the wrong track). Let ask you some question

Re: [gmx-users] HF/6-31G** ESP derived charges to replace PRODRG assigned ones

2009-03-27 Thread Ran Friedman, Biochemisches Inst.

Dear Josmar,

You haven't written which force field you plan to use. For OPLS and AMBER 
QM-based optimisation should be fine. In Gromos, the FF was developed with 
the aim of reproducing experimental results and I'm not sure if you can find 
a better solution than examining other residues with the same chemical 
moieties or use the same approach as reported in the relevant manuscripts. 
Some software packages can also be used - these are mostly proprietary and 
not so easy to use.


Once you derive the parameters, it's a good idea to make some test runs of 
the ligands and see if they behave as expected before you actually run a 
simulation with the protein. For example, if a conjugate ring system isn't 
planar something may be wrong in the setting.


There's no easy solution - this is why it's considered an advanced topic. It 
is, however, very important. I've encountered a ligand that leaves its 
binding site during a simulation due to wrong parameters (in this case, the 
protonation of a protein side chain - FEBS  581, Pages 4120-4124, 2007).


Hope that helped,
Ran

On Fri, 27 Mar 2009 12:22:01 -0700 (PDT)
 Josmar R. da Rocha bije...@yahoo.com.br wrote:

Dear users,

I have been reading some posts about using externally computed charges to 
replace Prodrg charges at ligand topology files. Many users commented on 
the low trustability given to Prodrg charges (e.g 
http://www.mail-archive.com/gmx-users@gromacs.org/msg02360.html ; 
http://www.mail-archive.com/gmx-users@gromacs.org/msg17351.html ). Dr. 
Verli pointed out the use of semi-empirical methods such as RM1 in cases 
not involving simulations with sulphate or phosphate groups (what is not my 
case) and the use of QM methods with the 6-31G** basis set, for example, to 
obtain robust charges 
(http://www.mail-archive.com/gmx-users@gromacs.org/msg03410.html). On the 
other hand Dr. Mobley defined as a a bad idea to compute charges for an 
all-atom case using QM and then try to convert these to a united atom force 
field. Other users advice that the best charges are that compatible with 
the force field parametrization
(http://www.mail-archive.com/gmx-users@gromacs.org/msg10760.html ; 
http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html), usually 
pointing to http://wiki.gromacs.org/index.php/Parameterization. Dr Friedman 
suggested that to calculate the electrostatic potential over the whole 
molecule, and fit the atomic charges so that they reproduce this potential 
in order to make it less sensitive to small changes in the geometry of the 
molecule may give good results 
(http://www.mail-archive.com/gmx-users@gromacs.org/msg08308.html). Dr. 
Lemkul stressed the need for charges refinement to reproduce 
experimentally-observed behavior while trying to use QM charges with Gromos 
ff. since Parameterization under Gromos usually involves empirical 
derivation of physical parameters, and free energy calculations using 
thermodynamic integration. 
Few examples of protein-ligand studies using Gromacs and Gromos96 ff that I 
have access (from literature) seem to treat it as take it for granted 
issue (any reference with a more detailed description would be welcome 
:-)). Despite reading on this topic I could not compile all the information 
in a clear and objective way (may be because I'm in the wrong track). Let 
ask you some question that I find would help me to make my ideas more 
clear:



1-am I overestimating the importance of ligand charges in such a simple 
study of protein-small molecule (containg charged Phosphate groups) 
complex? or


1.1-The only way to test for this is doing many different simulation on 
the same system using different type of computed charges to see what 
happen?


2-How could I try to choose a method to obtain reasonable charges based on 
the reproduction of experimentally-observed behavior if I do not have 
experimental data for my system?


3-I also would like to know from users dealing with protein-ligand 
interactions studies what do you consider a good approach to address this 
problem?


Based on what I read I'd have a tendency to use HF/6-31G** ESP derived 
charges (with necessary changes as to make it united-atom charges and 
scaling that to a integer number for each group). Please, let me know if 
that strategy would be as good as a disaster! 


Thank you very much for the attention.


Josmar Rocha



 Veja quais são os assuntos do momento no Yahoo! +Buscados
http://br.maisbuscados.yahoo.com




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Re: [gmx-users] Peptide aggregation

2008-09-20 Thread Ran Friedman, Biochemisches Inst.

Dear Leon,

Note that you can already use g_clustsize to check the aggregates. I'll 
contact you off list next week with the modified version.


Ran

On Fri, 19 Sep 2008 17:13:02 +0100
 Léon Salgado [EMAIL PROTECTED] wrote:

Dear Dr. Ran Friedman

Would you please be so kind to send me your version, to calculate then the 
rgyr of the largest aggregate.
The box was built with a layer of 1.2 nm around the solute (editconf -d 
1.2).


Leon

Ran Friedman wrote:

Dear Leon,

You can try to use g_clustsize to get the aggregates. I have a version
that can calculate the gyration radius of the largest aggregate, but
this would work only if your box is big enough and I haven't tried it
with rhombic dodecahedron boxes.

Ran.

Léon Salgado wrote:
  

Dear gmx users

I did some simulations of multimers (peptides) in rhombic dodecahedron
boxes. In the initial configuration of the system, the peptides are
close of each other in the center of the box.

My aim to see if the peptides do aggregate during the trajectory or if
they tend to stay apart. A rough estimate can be taken from the
gyration radius for all the peptides together.

Already did a trjconv -pbc nojump pre-treatment on the trajectory,
before calculating the Rgyr. The gyration.xvg plots sometimes do show
abrupt jumps, and this is surely due to boundary effects, if I
correctly understood the PBC idea. If a peptide approaches the
boundary, it appears on the opposite side, thus rgyr will show a false
sudden increase. In fact, the peptide could be closer to the rest of
the other peptide molecule(s).

Thus my question is:
how to deal with peptide clusters that span over the periodic boundaries?

A similar question was done by Singh:
http://www.gromacs.org/pipermail/gmx-users/2007-January/025474.html

and it  was suggested by Chris Neale to pre-process the trajectory
(see
http://www.gromacs.org/pipermail/gmx-users/2007-January/025481.html)
with:

trjconv -f a.xtc -o a_cluster.gro -e 0.001 -pbc cluster
grompp -f a.mdp -c a_cluster.gro -o a_cluster.tpr
trjconv -f a.xtc -o a_cluster.xtc -s a_cluster.tpr -pbc nojump

but I'm getting infinite loops on the -pbc cluster treatment, same as
reported by Chris
(http://www.gromacs.org/pipermail/gmx-users/2008-July/035343.html).

Best,
Léon

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--
Ran Friedman
Postdoctoral Fellow
Computational Structural Biology Group (A. Caflisch)
Institute of Biochemistry
University of Zurich
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
Tel. +41-44-6355593
Skype: ran.friedman
--

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Re: [gmx-users] Neutralizing the total charge of the system in vacuum

2007-11-24 Thread Ran Friedman, Biochemisches Inst.

Hello,

You can add a few ions manually or use genbox. However, it's probably better 
to use a vacuum force field and have your peptide uncharged for vacuum 
simulations. Any ions you add will have a very strong interaction with the 
peptide.


I assume you have a good reason to simulate in vacuo - the mailing list 
archives give many reasons why it's not advised.


Ran.

On Sat, 24 Nov 2007 19:47:43 +0200
 OZGE ENGIN [EMAIL PROTECTED] wrote:

Hi all,

I am performing a simulation in vacuum. The peptide has  nonzero charge, 
so I attempted to neutralize the total charge via genion;however as it is 
known, it asks for a continuous group for replacing, but I have no solvent 
molecules for the replacement.


How can I neutralize the total charge while performing simulations in 
vacuum?


Thanks in advance

Oz.

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--
Ran Friedman
Postdoctoral Fellow
Computational Structural Biology Group (A. Caflisch)
Institute of Biochemistry
University of Zurich
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
Tel. +41-44-6354493
Skype: ran.friedman
--

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Re: [gmx-users] quasiharmonic eigenvalue units / Schlitter entropy

2007-10-31 Thread Ran Friedman, Biochemisches Inst.

Dear Marcin,

You can contact me off list for a script that calculates the QH entropies 
from the output of g_covar. Also, IIRC there should be a version of g_covar 
that already does it somewhere (CVS-?).


Ran.

On Wed, 31 Oct 2007 17:40:45 +
 Marcin Krol [EMAIL PROTECTED] wrote:

Dear All,

Sorry for the repeated question, but I'm a bit lost when I want to get 
frequencies of modes from quasiharmonic analysis done with g_covar. From 
what I understood in QH
omega = sqrt(kT/lambda), where omega is the radial frequency, k - 
Boltzmann const, T-temp, and lambda is the eigenvalue. In order to get the 
units right lambda needs to be in length^2*mass units. Is it nm^2*amu?
I need the frequencies to calculate entropy estimate from QH analysis. 
However, another way of getting the entropy estimate would be to get it 
from Schlitter formula. Then, I wouldn't need to diagonalize the covariance 
matrix. Is there a way to request the calculation of Schlitter entropy 
after the covariance matrix is calculated, but before g_covar starts 
diagonalization?


Thanks in advance
marcin

--
Dr Marcin Krol
Biomolecular Modelling Laboratory
Cancer Research UK
e-mail: [EMAIL PROTECTED]
AND
Department of Bioinformatics
Collegium Medicum Jagiellonian University
e-mail: [EMAIL PROTECTED]

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--
Ran Friedman
Postdoctoral Fellow
Computational Structural Biology Group (A. Caflisch)
Institute of Biochemistry
University of Zurich
Winterthurerstrasse 190
CH-8057 Zurich, Switzerland
Tel. +41-44-6354493
Skype: ran.friedman
--

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