[gmx-users] add new residue and new atom

Justin Lemkul jalemkul at vt.edu
Fri Jan 29 18:24:40 CET 2016



On 1/29/16 12:22 PM, Malihe Hasanzadeh wrote:
> Dear Justin,
> Is there any way to get parameters of KCX residue for amber99sb-ildn?

Well, how did you get the ones you have?  And are you familiar with what the 
differences are between AMBER99sb and AMBER99sb-ILDN?

-Justin

> Thanks
> Malihe
>
> On Fri, Jan 29, 2016 at 8:45 PM, Justin Lemkul <jalemkul at vt.edu> wrote:
>
>>
>>
>> On 1/29/16 12:13 PM, Malihe Hasanzadeh wrote:
>>
>>> Dear justin,
>>> I forgot to write this step here, but I did this step also. I added (KCX
>>> Protein) in .dat file. But unfortunately as you say the gromacs dosen't
>>> identify my new residue!
>>>
>>
>> If this were true, pdb2gmx would not tell you otherwise.  You didn't do
>> what you thought you did, or you modified the wrong files.
>>
>> What should I do? Is my added parameters for KCX residue correct?
>>>
>>
>> Follow the steps exactly in the link I provided.  That's all there is to
>> it.
>>
>> -Justin
>>
>> Thanks
>>> Malihe
>>>
>>> On Fri, Jan 29, 2016 at 8:26 PM, Justin Lemkul <jalemkul at vt.edu> wrote:
>>>
>>>
>>>>
>>>> On 1/29/16 11:52 AM, Malihe Hasanzadeh wrote:
>>>>
>>>> Hi
>>>>>
>>>>> I used a PDB structure for MD simulation which it has a carbamylated Lys
>>>>> (KCX 220). This residue via carbamyl group bonded to metal in active
>>>>> site.
>>>>> So I had to define new residue(KCX), I copied parameters of Lys residue
>>>>> and
>>>>> added carbamyl group and added to .rtp file in amber force field
>>>>> (99sb)(gromacs5.0.4). I bring KCX parameters in below:
>>>>>       [ KCX ]
>>>>>     [ atoms ]
>>>>>         N    N           -0.34790     1
>>>>>         H    H            0.27470     2
>>>>>        CA    CT          -0.24000     3
>>>>>        HA    H1           0.14260     4
>>>>>        CB    CT          -0.00940     5
>>>>>       HB1    HC           0.03620     6
>>>>>       HB2    HC           0.03620     7
>>>>>        CG    CT           0.01870     8
>>>>>       HG1    HC           0.01030     9
>>>>>       HG2    HC           0.01030    10
>>>>>        CD    CT          -0.04790    11
>>>>>       HD1    HC           0.06210    12
>>>>>       HD2    HC           0.06210    13
>>>>>        CE    CT          -0.01430    14
>>>>>       HE1    HP           0.11350    15
>>>>>       HE2    HP           0.11350    16
>>>>>        NZ    N3          -0.38540    17
>>>>>       HZ1    H            0.34000    18
>>>>>       HZ2    H            0.34000    19
>>>>>       HZ3    H            0.34000    20
>>>>>         C    C            0.73410    21
>>>>>         O    O           -0.58940    22
>>>>>        CX    C            0.73410    23
>>>>>        HX    H            0.27470    24
>>>>>       OQ1    O           -0.58940    25
>>>>>       OQ2    O           -0.58940    26
>>>>>     [ bonds ]
>>>>>         N     H
>>>>>         N    CA
>>>>>        CA    HA
>>>>>        CA    CB
>>>>>        CA     C
>>>>>        CB   HB1
>>>>>        CB   HB2
>>>>>        CB    CG
>>>>>        CG   HG1
>>>>>        CG   HG2
>>>>>        CG    CD
>>>>>        CD   HD1
>>>>>        CD   HD2
>>>>>        CD    CE
>>>>>        CE   HE1
>>>>>        CE   HE2
>>>>>        CE    NZ
>>>>>        NZ   HZ1
>>>>>        NZ   HZ2
>>>>>        NZ   HZ3
>>>>>        NZ    CX
>>>>>         C     O
>>>>>        -C     N
>>>>>        CX   OQ1
>>>>>        CX   OQ2
>>>>>        CX    HX
>>>>>     [ impropers ]
>>>>>        -C    CA     N     H
>>>>>        CA    +N     C     O
>>>>>        NZ   OQ1    CX   OQ2
>>>>>
>>>>> In addition this protein has two Ni ion, that I added its parameters in
>>>>> .atp .itp and .dat files.
>>>>> Also my ligand has a F ion that when I docked with the protein, it
>>>>> closed
>>>>> to Ni ion in active site (distance 2.9 A). when I start MD simulation I
>>>>> faced with two problems:
>>>>>
>>>>> 1. when I run pdb2gmx gives many warning:
>>>>>
>>>>> Identified residue MET1 as a starting terminus.
>>>>> Warning: Residue KCX220 in chain has different type (Other) from
>>>>> starting
>>>>> residue MET1 (Protein).
>>>>> Warning: Residue ILE221 in chain has different type (Protein) from
>>>>> starting
>>>>> residue MET1 (Protein).
>>>>> Warning: Residue HIS222 in chain has different type (Protein) from
>>>>> starting
>>>>> residue MET1 (Protein).
>>>>> Warning: Residue GLU223 in chain has different type (Protein) from
>>>>> starting
>>>>> residue MET1 (Protein).
>>>>> Warning: Residue ASP224 in chain has different type (Protein) from
>>>>> starting
>>>>> residue MET1 (Protein).
>>>>> More than 5 unidentified residues at end of chain - disabling further
>>>>> warnings.
>>>>> Identified residue LEU219 as a ending terminus.
>>>>>
>>>>> My protein has 570 residue, but as you see the gromacs identified
>>>>> residue
>>>>> LEU219 as a ending terminus.!
>>>>>
>>>>> 2. when I used -missing option and continued my simulations, after
>>>>> energy
>>>>> minimization, I extract em.pdb file and I saw the distance between NI
>>>>> ion
>>>>> in active site with F ion in ligand is much more ( ~5 A) than before in
>>>>> complex.pdb. This means my ligand isn't stable in active site and it is
>>>>> moving away!
>>>>>
>>>>> please help me. what is my mistake?why ligand moving away and why
>>>>> gromacs
>>>>> doesn't identify end of the protein? Is there a relationship between
>>>>> added
>>>>> parameters and getting away of ligand?
>>>>>
>>>>>
>>>>> You forgot step 5:
>>>>
>>>> http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field
>>>>
>>>> pdb2gmx writes your custom residue as its own chain, not bonded to the
>>>> rest of the protein, so it is its own separate molecule.
>>>>
>>>> -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
>>>>
>>>> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
>>>> http://mackerell.umaryland.edu/~jalemkul
>>>>
>>>> ==================================================
>>>> --
>>>> Gromacs Users mailing list
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>>>>
>> --
>> ==================================================
>>
>> 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
>>
>> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
>> http://mackerell.umaryland.edu/~jalemkul
>>
>> ==================================================
>> --
>> Gromacs Users mailing list
>>
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-- 
==================================================

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

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

==================================================


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