[gmx-users] Hydrogens of ATB ligand show obvious vibration under all-bonds contraints?

Justin Lemkul jalemkul at vt.edu
Thu Oct 17 17:17:59 CEST 2019



On 10/17/19 11:02 AM, Du, Yu wrote:
> Dear GMX-Users,
>
> I'm using GMX2018.3 simulating Melatonin (ATB Link: https://atb.uq.edu.au/molecule.py?molid=355098).
>
>
> I found that the hydrogens of two methyl groups (CH3, i.e. CH11, CH12, CH13, CH14, CH15 and CH16) showed
> obvious vibration under the following mdp configuration:
>
>
> integrator      = md
> dt           = 0.002
> cutoff-scheme    = group
> constraints     = all-bonds
> constraint_algorithm = lincs
> continuation      = yes
>
>
> I used the gromos54a7_atb.ff.
>
>
>
>
> P.S. The partial topology of Melatonin from ATB

You're using the wrong topology. GROMOS parameter sets are united-atom, 
but you've chosen the all-atom topology (no idea why this exists, 
honestly). Your CH3 and CH2 groups should have no explicit H atoms.

-Justin

> [ moleculetype ]
> ; Name   nrexcl
> ESV6     3
> [ atoms ]
> ;  nr  type  resnr  resid  atom  cgnr  charge    mass
>      1    HC    1    ESV6    H16    1    0.067   1.0080
>      2  CPos    1    ESV6    C13    2    0.010  12.0110
>      3    HC    1    ESV6    H14    3    0.067   1.0080
>      4    HC    1    ESV6    H15    4    0.067   1.0080
>      5    OE    1    ESV6     O1    5   -0.368  15.9994
>      6  CAro    1    ESV6     C9    6    0.398  12.0110
>      7  CAro    1    ESV6     C7    7   -0.385  12.0110
>      8    HC    1    ESV6     H7    8    0.163   1.0080
>      9  CAro    1    ESV6     C2    9    0.085  12.0110
>     10  CAro    1    ESV6     C1   10   -0.057  12.0110
>     11  CAro    1    ESV6     C5   11   -0.144  12.0110
>     12    HC    1    ESV6     H3   12    0.186   1.0080
>     13  NOpt    1    ESV6     N1   13   -0.354  14.0067
>     14  HS14    1    ESV6     H6   14    0.373   1.0080
>     15  CAro    1    ESV6     C4   15    0.070  12.0110
>     16  CAro    1    ESV6     C8   16   -0.145  12.0110
>     17    HC    1    ESV6     H8   17    0.156   1.0080
>     18  CAro    1    ESV6    C10   18   -0.360  12.0110
>     19    HC    1    ESV6     H9   19    0.169   1.0080
>     20     C    1    ESV6     C3   20   -0.159  12.0110
>     21    HC    1    ESV6     H1   21    0.070   1.0080
>     22    HC    1    ESV6     H2   22    0.070   1.0080
>     23  CPos    1    ESV6     C6   23    0.231  12.0110
>     24    HC    1    ESV6     H4   24    0.014   1.0080
>     25    HC    1    ESV6     H5   25    0.014   1.0080
>     26     N    1    ESV6     N2   26   -0.525  14.0067
>     27  HS14    1    ESV6    H10   27    0.307   1.0080
>     28  CPos    1    ESV6    C11   28    0.684  12.0110
>     29 OEOpt    1    ESV6     O2   29   -0.616  15.9994
>     30     C    1    ESV6    C12   30   -0.586  12.0110
>     31    HC    1    ESV6    H11   31    0.166   1.0080
>     32    HC    1    ESV6    H12   32    0.166   1.0080
>     33    HC    1    ESV6    H13   33    0.166   1.0080
> ; total charge of the molecule:   0.000
> [ bonds ]
> ;  ai   aj  funct   c0         c1
>      1    2    2   0.1090   1.2300e+07
>      2    3    2   0.1090   1.2300e+07
>      2    4    2   0.1090   1.2300e+07
>      2    5    2   0.1430   8.1800e+06
>      5    6    2   0.1380   4.4633e+06
>      6    7    2   0.1390   8.6600e+06
>      6   18    2   0.1420   3.2236e+06
>      7    8    2   0.1090   1.2300e+07
>      7    9    2   0.1410   6.5389e+06
>      9   10    2   0.1435   6.1000e+06
>      9   15    2   0.1430   8.1800e+06
>     10   11    2   0.1380   1.1000e+07
>     10   20    2   0.1500   8.3700e+06
>     11   12    2   0.1090   1.2300e+07
>     11   13    2   0.1380   1.1000e+07
>     13   14    2   0.1010   6.3719e+06
>     13   15    2   0.1380   1.1000e+07
>     15   16    2   0.1400   8.5400e+06
>     16   17    2   0.1090   1.2300e+07
>     16   18    2   0.1390   8.6600e+06
>     18   19    2   0.1090   1.2300e+07
>     20   21    2   0.1090   1.2300e+07
>     20   22    2   0.1090   1.2300e+07
>     20   23    2   0.1540   4.0057e+06
>     23   24    2   0.1090   1.2300e+07
>     23   25    2   0.1090   1.2300e+07
>     23   26    2   0.1460   4.6913e+06
>     26   27    2   0.1010   6.3719e+06
>     26   28    2   0.1360   1.0200e+07
>     28   29    2   0.1230   1.6600e+07
>     28   30    2   0.1520   5.4300e+06
>     30   31    2   0.1090   1.2300e+07
>     30   32    2   0.1090   1.2300e+07
>     30   33    2   0.1090   1.2300e+07
>
>
>
>
> --
> Du, Yu
> PhD Student,
> Shanghai Institute of Organic Chemistry
> 345 Ling Ling Rd., Shanghai, China.
> Zip: 200032, Tel: (86) 021 5492 5275

-- 
==================================================

Justin A. Lemkul, Ph.D.
Assistant Professor
Office: 301 Fralin Hall
Lab: 303 Engel Hall

Virginia Tech Department of Biochemistry
340 West Campus Dr.
Blacksburg, VA 24061

jalemkul at vt.edu | (540) 231-3129
http://www.thelemkullab.com

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



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