[gmx-users] g_dist error

Thomas Schlesier schlesi at uni-mainz.de
Tue Sep 13 15:02:33 CEST 2011


never used the -dist option, but i think you have here a missunderstanding:

 >>> t: 275  20230 SOL 62618 OW  0.341434 (nm)

i think this means: at time=275 atom 62618 (which is a OW) from residue 
20230 (which is a SOL) is 0.341434nm away from your protein atom.

the x SOL y OW means not the distance between some SOl-atom and OW, but 
that the OW atom is from the residue x from the SOL group!!!


 >>> And when am already specifying only one atom from protein ie say 
1322. why
 >>> do i get this kind of output-
 >>> t: 275  20230 SOL 62618 OW  0.341434 (nm)
 >>> t: 275  22019 SOL 67985 OW  0.171584 (nm)
 >>> t: 276  10768 SOL 34232 OW  0.303328 (nm)
 >>> t: 276  20230 SOL 62618 OW  0.325176 (nm)
...

you get this output, because the programm assumes that you remember 
which was group 1 and so it does not need to write it in every line.

since i never used the -dist option, the stuff above could be false, so 
short thing you can do is and look if atom 62618 is in residue 20230, 
and then the above should be right.

greetings
thomas



> Date: Tue, 13 Sep 2011 13:32:26 +0530
> From: aiswarya pawar<aiswarya.pawar at gmail.com>
> Subject: Re: [gmx-users] g_dist error
> To: Discussion list for GROMACS users<gmx-users at gromacs.org>
> Message-ID:
> 	<CAEa6cRA+7W5Hed_KHtPN3cqmPD8xyE5ZJrS-HSap6-2C6h2=9w at mail.gmail.com>
> Content-Type: text/plain; charset="iso-8859-1"
>
> g_dist -f md.xtc -s md.tpr -dist 0.5 -e 500 if the index name not given it
> takes the default index file, so there isnt any wrong in selecting the
> atoms.
>
> On Tue, Sep 13, 2011 at 1:24 PM, Mark Abraham<Mark.Abraham at anu.edu.au>wrote:
>
>>   On 13/09/2011 4:14 PM, aiswarya pawar wrote:
>>
>> Mark,
>>
>> the command line goes like this-
>>
>> g_dist -f md.xtc -s md.tpr -dist 0.5 -e 500
>>
>>
>> This command line is not using an index file. The index groups defined for
>> the grompp that produced the .tpr are being used (which may be the default
>> ones, depending what you did). Please copy and show the interactive input
>> you made to g_dist after it showed the groups it knew about.
>>
>>
>>
>> the index file has group1- a_1322 ( this is just a single atom from a
>> protein. its in sidechain)
>>                            group2- a_OW ( this is water atoms)
>>
>>
>> Your output is listing the time of the frame, and the residue number,
>> residue name, atom number, and atom name of the matching atom. Apparently a
>> water molecule can sometimes be closer than 0.2nm, and sometimes not.
>>
>> Mark
>>
>>
>>
>> now as per the utility it should give me and output as-
>>
>> t:1 1322 a 54119 OW 0.389
>>
>> but am getting something different
>>
>> On Tue, Sep 13, 2011 at 11:24 AM, Mark Abraham<Mark.Abraham at anu.edu.au>wrote:
>>
>>>   On 13/09/2011 3:40 PM, aiswarya pawar wrote:
>>>
>>>
>>> Hi Mark,
>>>
>>> The -dist option says- print all the atoms in group 2 that are closer than
>>> a certain distance to the center of mass of group 1.
>>> That means it should give me the distance from OW to protein atom.
>>>
>>>
>>>   If you choose correct groups that are correctly defined with respect to
>>> your trajectory and use a large enough distance cutoff.
>>>
>>>
>>>
>>> And when am already specifying only one atom from protein ie say 1322. why
>>> do i get this kind of output-
>>>
>>>
>>>   We can't tell. We don't know what your command line is, what's in your
>>> simulation system, the contents of your index groups, or which groups you've
>>> selected for which role. Clearly something is not working properly, and our
>>> time constraints mean that we're going to assume you've done something
>>> wrong, in the absence of evidence to the contrary.
>>>
>>> Mark
>>>
>>>
>>>
>>> t: 275  20230 SOL 62618 OW  0.341434 (nm)
>>> t: 275  22019 SOL 67985 OW  0.171584 (nm)
>>> t: 276  10768 SOL 34232 OW  0.303328 (nm)
>>> t: 276  20230 SOL 62618 OW  0.325176 (nm)
>>> t: 276  22019 SOL 67985 OW  0.187259 (nm)
>>> t: 277  10768 SOL 34232 OW  0.306008 (nm)
>>> t: 277  20230 SOL 62618 OW  0.326195 (nm)
>>> t: 277  22019 SOL 67985 OW  0.181089 (nm)
>>> t: 278  10768 SOL 34232 OW  0.274507 (nm)
>>> t: 278  22019 SOL 67985 OW  0.292652 (nm)
>>> t: 279  10618 SOL 33782 OW  0.319922 (nm)
>>> t: 280  10618 SOL 33782 OW  0.330082 (nm)
>>> t: 280  22019 SOL 67985 OW  0.330203 (nm)
>>> t: 281  8273 SOL 26747 OW  0.278731 (nm)
>>> t: 281  10618 SOL 33782 OW  0.325434 (nm)
>>> t: 281  11535 SOL 36533 OW  0.200327 (nm)
>>> t: 281  17036 SOL 53036 OW  0.343946 (nm)
>>> t: 282  8273 SOL 26747 OW  0.256558 (nm)
>>> t: 282  11535 SOL 36533 OW  0.327147 (nm)
>>> t: 283  8273 SOL 26747 OW  0.165061 (nm)
>>> t: 283  10618 SOL 33782 OW  0.306578 (nm)
>>> t: 283  17191 SOL 53501 OW  0.333075 (nm)
>>> t: 284  8273 SOL 26747 OW  0.19427 (nm)
>>> t: 284  10618 SOL 33782 OW  0.321927 (nm)
>>> t: 284  17191 SOL 53501 OW  0.30832 (nm)
>>>
>>>
>>>
>>>
>>> On Tue, Sep 13, 2011 at 10:40 AM, Mark Abraham<Mark.Abraham at anu.edu.au>wrote:
>>>
>>>>   On 13/09/2011 2:27 PM, aiswarya.pawar at gmail.com wrote:
>>>>
>>>> Iam -dist option because I need the distance between two groups
>>>>
>>>>
>>>>   That is not what g_dist -dist does. Please read g_dist -h.
>>>>
>>>>
>>>>    excluding -dist gives me X,Y,Z output which I don't want.
>>>>
>>>>
>>>>   And other output which you do, but you have to use -o to get it. Read
>>>> g_dist -h.
>>>>
>>>>
>>>>    And am not specifying an -o.
>>>>
>>>>
>>>>   You need to specify -o to achieve your purpose. However, as I said quite
>>>> a while ago, there is no value in measuring the distance between a protein
>>>> phase and a water phase if they are in contact...
>>>>
>>>> Mark
>>>>
>>>>
>>>>   Sent from my BlackBerry? on Reliance Mobile, India's No. 1 Network. Go for it!
>>>>
>>>> -----Original Message-----
>>>> From: "Justin A. Lemkul"<jalemkul at vt.edu>  <jalemkul at vt.edu>
>>>> Date: Mon, 12 Sep 2011 22:35:28
>>>> To:<aiswarya.pawar at gmail.com>  <aiswarya.pawar at gmail.com>; Discussion list for GROMACS users<gmx-users at gromacs.org>  <gmx-users at gromacs.org>
>>>> Reply-To: jalemkul at vt.edu
>>>> Subject: Re: [gmx-users] g_dist error
>>>>
>>>>
>>>> aiswarya.pawar at gmail.com wrote:
>>>>
>>>>   Even if I specify an atom say 1277 atom number to find distance against the OW atoms. I get the same result of SOL-OW distance. Is it a bug cause even after specifying one atom from a protein why doesn't it give me the result for the SOL.
>>>>
>>>>
>>>>
>>>>   As was suggested several messages ago, please do NOT combine -o and -dist.  If
>>>> you want to measure a distance, use -o.  If you want g_dist to print a list of
>>>> atoms that satisfy some given criteria, use -dist, but not together.
>>>>
>>>> -Justin
>>>>
>>>>
>>>>   Thanks
>>>> Sent from my BlackBerry? on Reliance Mobile, India's No. 1 Network. Go for it!
>>>>
>>>> -----Original Message-----
>>>> From: "Justin A. Lemkul"<jalemkul at vt.edu>  <jalemkul at vt.edu>
>>>> Sender: gmx-users-bounces at gromacs.org
>>>> Date: Mon, 12 Sep 2011 07:52:54
>>>> To: Discussion list for GROMACS users<gmx-users at gromacs.org>  <gmx-users at gromacs.org>
>>>> Reply-To: jalemkul at vt.edu,
>>>> 	Discussion list for GROMACS users<gmx-users at gromacs.org>  <gmx-users at gromacs.org>
>>>> Subject: Re: [gmx-users] g_dist error
>>>>
>>>>
>>>>
>>>> aiswarya pawar wrote:
>>>>
>>>>   hi Justin,
>>>>
>>>> As far i referred the OW,HW1 etc are water atoms so how can it be
>>>> distance between the SOL protein atoms, instead it is SOL water atoms.
>>>>
>>>>
>>>>   The printed distance indicates that there is a certain water molecule that is
>>>> just over 2 hydrogen bonding lengths away from your protein's backbone.  Sounds
>>>> normal to me.
>>>>
>>>> -Justin
>>>>
>>>>
>>>>   Thanks
>>>>
>>>> On Mon, Sep 12, 2011 at 4:49 PM, Justin A. Lemkul<jalemkul at vt.edu<mailto:jalemkul at vt.edu>  <jalemkul at vt.edu>>  wrote:
>>>>
>>>>
>>>>
>>>>      aiswarya pawar wrote:
>>>>
>>>>          Hi Users,
>>>>
>>>>          Am using g_dist to find the distance between water and protein.
>>>>          but my output has the values of SOL-water distance.
>>>>
>>>>          t: 1  136 SOL 2336 OW  0.772373 (nm)
>>>>
>>>>
>>>>      This is not a water-water distance, it is the output of the -dist
>>>>      option telling you that water molecule 136 has its OW atom at
>>>>      0.7723273 nm from whatever your reference group is.
>>>>
>>>>      -Justin
>>>>
>>>>      --
>>>>      ==============================__==========
>>>>
>>>>      Justin A. Lemkul
>>>>      Ph.D. Candidate
>>>>      ICTAS Doctoral Scholar
>>>>      MILES-IGERT Trainee
>>>>      Department of Biochemistry
>>>>      Virginia Tech
>>>>      Blacksburg, VA
>>>>      jalemkul[at]vt.edu<http://vt.edu>  <http://vt.edu>  | (540) 231-9080
>>>>      http://www.bevanlab.biochem.__vt.edu/Pages/Personal/justin
>>>>      <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>  <http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>
>>>>
>>>>      ==============================__==========
>>>>      --
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>>>
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>>>
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>>
>>
>>
>>
>>
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