[gmx-users] No default U-B types in CHARMM36 FF

Justin Lemkul jalemkul at vt.edu
Sun Apr 13 15:51:31 CEST 2014



On 4/13/14, 6:39 AM, Mark Abraham wrote:
> Hi,
>
> Looks like nobody has parametrized that interaction. Not too surprising,
> though, since you won't often get NH2 in water at biological pH!
>

Yep, just another obscure case that was never deemed important enough to 
parametrize.  Assigning parameters by analogy here is probably safe enough, e.g. 
the H-NH2-CT1 parameters can be used for H-NH2-CT2.

-Justin

> Mark
> On Apr 13, 2014 10:16 AM, "Albert" <mailmd2011 at gmail.com> wrote:
>
>> Hello:
>>
>> I am running command:
>>
>> grompp -f em.mdp -c ion-em.pdb -o test.tpr
>>
>>
>> but it failed with messages:
>>
>>
>>
>> ------------------------------------------------------------
>> -----------------------------------------
>>
>> Generated 71611 of the 71631 non-bonded parameter combinations
>> Generating 1-4 interactions: fudge = 1
>> Generated 45719 of the 71631 1-4 parameter combinations
>>
>> ERROR 1 [file topol.top, line 22781]:
>>    No default U-B types
>>
>> -------------------------------------------------------
>> Program grompp, VERSION 4.6.5
>> Source code file: /home/albert/gromacs-4.6.5/src/kernel/grompp.c, line:
>> 1610
>>
>> Fatal error:
>> There were 13 errors in input file(s)
>> For more information and tips for troubleshooting, please check the GROMACS
>> website at http://www.gromacs.org/Documentation/Errors
>> -------------------------------------------------------
>>
>>
>>
>> I checked the line 22781, it was the last line of following:
>>
>> [ angles ]
>> ;  ai    aj    ak funct            c0            c1 c2            c3
>>      2     1     3     5
>>      2     1     4     5  (<---this line)
>>
>>
>>
>> Here is my initial residues:
>>
>>
>> [ atoms ]
>> ;   nr       type  resnr residue  atom   cgnr     charge       mass typeB
>>     chargeB      massB
>> ; residue  36 GLY rtp GLY  q  0.0
>>       1        NH2     36    GLY      N      1      -0.96 14.007   ; qtot
>> -0.96
>>       2          H     36    GLY    HT1      2       0.34 1.008   ; qtot
>> -0.62
>>       3          H     36    GLY    HT2      3       0.34 1.008   ; qtot
>> -0.28
>>       4        CT2     36    GLY     CA      4        0.1 12.011   ; qtot
>> -0.18
>>       5        HB2     36    GLY    HA1      5       0.09 1.008   ; qtot
>> -0.09
>>       6        HB2     36    GLY    HA2      6       0.09 1.008   ; qtot 0
>>       7          C     36    GLY      C      7       0.51 12.011   ; qtot
>> 0.51
>>       8          O     36    GLY      O      8      -0.51 15.999   ; qtot 0
>> ; residue  37 SER rtp SER  q  0.0
>>       9        NH1     37    SER      N      9      -0.47 14.007   ; qtot
>> -0.47
>>      10          H     37    SER     HN     10       0.31 1.008   ; qtot
>> -0.16
>>      11        CT1     37    SER     CA     11       0.07 12.011   ; qtot
>> -0.09
>>      12        HB1     37    SER     HA     12       0.09 1.008   ; qtot 0
>>      13        CT2     37    SER     CB     13       0.05 12.011   ; qtot
>> 0.05
>>      14        HA2     37    SER    HB1     14       0.09 1.008   ; qtot
>> 0.14
>>      15        HA2     37    SER    HB2     15       0.09 1.008   ; qtot
>> 0.23
>>      16        OH1     37    SER     OG     16      -0.66 15.999   ; qtot
>> -0.43
>>      17          H     37    SER    HG1     17       0.43 1.008   ; qtot 0
>>      18          C     37    SER      C     18       0.51 12.011   ; qtot
>> 0.51
>>      19          O     37    SER      O     19      -0.51 15.999   ; qtot 0
>> ; residue  38 PRO rtp PRO  q  0.0
>>      20          N     38    PRO      N     20      -0.29 14.007   ; qtot
>> -0.29
>>      21        CP3     38    PRO     CD     21          0 12.011   ; qtot
>> -0.29
>>      22        HA2     38    PRO    HD1     22       0.09 1.008   ; qtot
>> -0.2
>>      23        HA2     38    PRO    HD2     23       0.09 1.008   ; qtot
>> -0.11
>>      24        CP1     38    PRO     CA     24       0.02 12.011   ; qtot
>> -0.09
>>      25        HB1     38    PRO     HA     25       0.09 1.008   ; qtot 0
>>      26        CP2     38    PRO     CB     26      -0.18 12.011   ; qtot
>> -0.18
>>      27        HA2     38    PRO    HB1     27       0.09 1.008   ; qtot
>> -0.09
>>      28        HA2     38    PRO    HB2     28       0.09 1.008   ; qtot 0
>>      29        CP2     38    PRO     CG     29      -0.18 12.011   ; qtot
>> -0.18
>>      30        HA2     38    PRO    HG1     30       0.09 1.008   ; qtot
>> -0.09
>>      31        HA2     38    PRO    HG2     31       0.09 1.008   ; qtot 0
>>      32          C     38    PRO      C     32       0.51 12.011   ; qtot
>> 0.51
>>      33          O     38    PRO      O     33      -0.51 15.999   ; qtot 0
>> ; residue  39 GLY rtp GLY  q  0.0
>>      34        NH1     39    GLY      N     34      -0.47 14.007   ; qtot
>> -0.47
>>      35          H     39    GLY     HN     35       0.31 1.008   ; qtot
>> -0.16
>>      36        CT2     39    GLY     CA     36      -0.02 12.011   ; qtot
>> -0.18
>>      37        HB2     39    GLY    HA1     37       0.09 1.008   ; qtot
>> -0.09
>>      38        HB2     39    GLY    HA2     38       0.09 1.008   ; qtot 0
>>      39          C     39    GLY      C     39       0.51 12.011   ; qtot
>> 0.51
>>      40          O     39    GLY      O     40      -0.51 15.999   ; qtot 0
>>
>>
>> I used command:
>>
>> pdb2gmx -f p.pdb -o gmx.pdb -ter
>>
>> to generate the topology file, and I assinged: GLY-NH2 for the first
>> residue GLY, -COOH for the last residue.
>>
>> thank you very much.
>>
>> best
>> Albert
>>
>>
>>
>>
>>
>>
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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 601
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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