[gmx-users] Making Disulfide Bonds

James Starlight jmsstarlight at gmail.com
Sat Apr 28 16:25:41 CEST 2012


Francesco,

Thanks, I find your aproach very handfull :)

Justin,

in that example I've defined in minim.mdp

*disre = simple

**disre_f = 5000

in the topology.top I've included

* [ distance_restraints ]
   ; ai aj type index type’ low up1 up2 fac
      1 10  1    0     1    0.18 0.20 0.22 1.0

where 1 and 10 the numbers of the S atoms of both Cys residues. and 0.2 is
the disered distance between wich I want to obtain after such minimisation.
*


As the consequence no changes have been detected after such CG minimisation
:( What I've forgotten ?

James


*
2012/4/28 Justin A. Lemkul <jalemkul at vt.edu>

>
>
> On 4/28/12 10:08 AM, James Starlight wrote:
>
>> .. and the main question- what should be in mdp file of such restrained
>> minimisation ?
>>
>> Today I've done vry properly minimisation of such system in vacuum with
>> the CG
>> minimisator and applied disres ( above example ) with big force constant (
>> disres options have been defined in the minim.mdp file ). As the result I
>> have
>> not noticed any perturbation in the distance between two S-S atoms the
>> distance
>> between wich I've constrained.
>>
>>
> You need to add the applicable distance restraint settings for them to be
> utilized.
>
> http://manual.gromacs.org/**online/mdp_opt.html#nmr<http://manual.gromacs.org/online/mdp_opt.html#nmr>
>
> -Justin
>
>
>>
>> 2012/4/28 James Starlight <jmsstarlight at gmail.com <mailto:
>> jmsstarlight at gmail.com**>>
>>
>>
>>    Hi Francesco!
>>
>>    So I must define in the current topology the disres bettwen two S
>> atoms ( in
>>    the below example 1 and 10 ) to apply hormonic restains
>>
>>    [ distance_restraints ]
>>    ; ai aj type index type’ low up1 up2 fac
>>
>>
>>       1 10  1    0     1    0.18 0.20 0.22 1.0
>>
>>    to restrain this atoms within 0.2 nm. Does it correct ? Or should I
>> use some other disres for such task ?
>>
>>    James
>>
>>
>>
>>    2012/4/28 francesco oteri <francesco.oteri at gmail.com
>>    <mailto:francesco.oteri at gmail.**com <francesco.oteri at gmail.com>>>
>>
>>
>>        Hi James,
>>        usually people run a minimization using distance restrain on the
>> two
>>        atoms in order to
>>        make them closer.
>>        Then the obtained cnfiguration is used to recalculate the topology.
>>
>>        Francesco
>>
>>        2012/4/28 James Starlight <jmsstarlight at gmail.com
>>        <mailto:jmsstarlight at gmail.com**>>
>>
>>
>>            Dear Gromacs Users!
>>
>>            I have a model of my protein wich has 4 S-S bounds in the loop
>>            regions. So I want to define in topology all those four S-S
>> linkage.
>>
>>            Unfortunatelly one of that S-S have not been recognised by
>> Gromacs (
>>            Also I've tried to check this bond in pymol and found that
>> distance
>>            between that two Cys Cys are larger for S-S occurence) due to
>> some
>>            inaccyracy of model.
>>
>>            Is there any way to define such missing S-S manually? On the
>> gromacs
>>            site I've found possible sollution by means of spechbond.dat
>>            editing. I've tried to increase distance between S-S atoms but
>> this
>>            have not had desirebly affect.
>>
>>            In the topology.top file I've found that the S-S bonds
>> beetween S
>>            atoms are defined in the bond section without any type for
>> such bond
>>            type. Also I've found that the same enties are present in the
>> angle
>>            and dihedralls sections.  Could I define the same contact only
>> in
>>            the bond section and further minimise my system to obtain new
>> S-S
>>            linckage or should I also define all other enties ( like
>> dihedralls
>>            etc) for that bond ?
>>
>>
>>            Thanks for help
>>
>>
>>            James
>>
>>            --
>>            gmx-users mailing list gmx-users at gromacs.org
>>            <mailto:gmx-users at gromacs.org>
>>
>>            http://lists.gromacs.org/**mailman/listinfo/gmx-users<http://lists.gromacs.org/mailman/listinfo/gmx-users>
>>            Please search the archive at
>>            http://www.gromacs.org/**Support/Mailing_Lists/Search<http://www.gromacs.org/Support/Mailing_Lists/Search>before posting!
>>            Please don't post (un)subscribe requests to the list. Use the
>>            www interface or send it to gmx-users-request at gromacs.org
>>            <mailto:gmx-users-request@**gromacs.org<gmx-users-request at gromacs.org>
>> >.
>>
>>            Can't post? Read http://www.gromacs.org/**
>> Support/Mailing_Lists <http://www.gromacs.org/Support/Mailing_Lists>
>>
>>
>>
>>
>>        --
>>        Cordiali saluti, Dr.Oteri Francesco
>>
>>        --
>>        gmx-users mailing list gmx-users at gromacs.org <mailto:
>> gmx-users at gromacs.org>
>>
>>        http://lists.gromacs.org/**mailman/listinfo/gmx-users<http://lists.gromacs.org/mailman/listinfo/gmx-users>
>>        Please search the archive at
>>        http://www.gromacs.org/**Support/Mailing_Lists/Search<http://www.gromacs.org/Support/Mailing_Lists/Search>before posting!
>>        Please don't post (un)subscribe requests to the list. Use the
>>        www interface or send it to gmx-users-request at gromacs.org
>>        <mailto:gmx-users-request@**gromacs.org<gmx-users-request at gromacs.org>
>> >.
>>
>>        Can't post? Read http://www.gromacs.org/**Support/Mailing_Lists<http://www.gromacs.org/Support/Mailing_Lists>
>>
>>
>>
>>
>>
>>
> --
> ==============================**==========
>
> Justin A. Lemkul
> Ph.D. Candidate
> ICTAS Doctoral Scholar
> MILES-IGERT Trainee
> Department of Biochemistry
> Virginia Tech
> Blacksburg, VA
> jalemkul[at]vt.edu | (540) 231-9080
> http://www.bevanlab.biochem.**vt.edu/Pages/Personal/justin<http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin>
>
> ==============================**==========
>
> --
> gmx-users mailing list    gmx-users at gromacs.org
> http://lists.gromacs.org/**mailman/listinfo/gmx-users<http://lists.gromacs.org/mailman/listinfo/gmx-users>
> Please search the archive at http://www.gromacs.org/**
> Support/Mailing_Lists/Search<http://www.gromacs.org/Support/Mailing_Lists/Search>before posting!
> Please don't post (un)subscribe requests to the list. Use the www
> interface or send it to gmx-users-request at gromacs.org.
> Can't post? Read http://www.gromacs.org/**Support/Mailing_Lists<http://www.gromacs.org/Support/Mailing_Lists>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://maillist.sys.kth.se/pipermail/gromacs.org_gmx-users/attachments/20120428/4fb41149/attachment.html>


More information about the gromacs.org_gmx-users mailing list