GROMACS version:2020.6
GROMACS modification:No
Good afternoon everyone,
I would like to simulate Mg2+ ion in tip4p-2005 water, using the madrid2019 FF ( Cookie Absent ).
In the Supp.Info of the paper there is a topology.top including both the parameters of the ions and of the water model.
My idea was to create a box of tip4p-2005 water with
- gmx solvate -cs tip4p.gro -o water_box.gro -box 3 3 3 -p topol.top
and then add the ion with gmx solvate. However, when I do the grompp step:
- gmx grompp -f ions.mdp -p topol.top -c water_box.gro -o ions.tpr
I get the error
“Fatal error:
No molecules were defined in the system”.
The only molecules I added are the water molecules (SOL), however I don t see why this is a problem.
Below I put the topol.top from the Supp Info, before I begun the procedure I deleted the content of section [molecules], since these are not the atoms I want to simulate.
Any help is appreciated,
Giulia
“”"
[ defaults ]
; nbfunc comb-rule gen-pairs fudgeLJ fudgeQQ
1 2 no 1.0 1.0
[atomtypes]
;name mass charge ptype sigma epsilon
Na 22.9898 0.850 A 0.22173668 1.47235577
Mg 24.305 1.700 A 0.11629000 3.65190000
Ca 40.078 1.700 A 0.26656000 0.50720000
K 39.0983 0.850 A 0.23014000 1.98574000
Li 6.94100 0.850 A 0.14397000 0.43508986
Cl 35.4530 -0.850 A 0.46990563 0.07692308
OSO4 24.01565 -0.650 A 0.36500000 0.83740000
SSO4 0 0.900 D 0.35500000 1.04670000
IW 0 0.000 D 0.00000000 0.00000000
OWT4 15.9994 0.000 A 0.31589000 0.77490765
HW 1.00794 0.000 A 0.00000000 0.00000000
[nonbond_params]
;i j func sigma epsilon
Cl OWT4 1 0.42386698 0.06198347
Na OWT4 1 0.26083754 0.79338830
Na Cl 1 0.30051231 1.43889423
Mg OWT4 1 0.18100000 12.0000000
Mg Cl 1 0.30000000 3.00000000
Ca OWT4 1 0.24000000 7.25000000
Ca Cl 1 0.31500000 1.00000000
K OWT4 1 0.28904000 1.40043000
K Cl 1 0.33970000 1.40000000
Li OWT4 1 0.21200000 0.70065003
Li Cl 1 0.27000000 1.28294385
OSO4 OWT4 1 0.34044500 0.62900000
Mg OSO4 1 0.24064500 2.74874271
K OSO4 1 0.32000000 1.28951878
Li OSO4 1 0.28448500 0.80360935
[moleculetype]
; name nrexcl
water 1
[atoms]
; nr type resnr residu atom cgnr charge
1 OWT4 1 water OW1 1 0 15.9994
2 HW 1 water HW2 1 0.5564 1.00794
3 HW 1 water HW3 1 0.5564 1.00794
4 IW 1 water MW4 1 -1.1128 0.0
[constraints]
;i j funct doh dhh
1 2 1 0.09572
1 3 1 0.09572
2 3 1 0.15139
[exclusions]
1 2 3 4
2 1 3 4
3 1 2 4
4 1 2 3
; The position of the dummy is computed as follows:
;
; O
;
; D
;
; H H
;
; const = distance (OD) / [ cos (angle(DOH)) * distance (OH) ]
; 0.015 nm / [ cos (52.26 deg) * 0.09572 nm ]
; Dummy pos x4 = x1 + a*(x2-x1) + b*(x3-x1)
[dummies3]
; Dummy from funct a b
4 1 2 3 1 0.13193828 0.13193828
[moleculetype]
; name nrexcl
Na 1
[atoms]
; nr type resnr residu atom cgnr charge
1 Na 1 Na Na 1 0.8500 22.9898
[moleculetype]
; name nrexcl
Cl 1
[atoms]
; nr type resnr residu atom cgnr charge
1 Cl 1 Cl Cl 1 -0.8500 35.453
[ moleculetype ]
; molname nrexcl
Mg 1
[ atoms ]
; id at type res nr residu name at name cg nr charge mass
1 Mg 1 Mg Mg 1 1.7 24.3050
[ moleculetype ]
; molname nrexcl
Ca 1
[ atoms ]
; id at type res nr residu name at name cg nr charge mass
1 Ca 1 Ca Ca 1 1.7 40.078
[moleculetype]
; name nrexcl
K 1
[atoms]
; nr type resnr residu atom cgnr charge
1 K 1 K K 1 0.8500 39.0983
[moleculetype]
; name nrexcl
Li 1
[atoms]
; nr type resnr residu atom cgnr charge
1 Li 1 Li Li 1 0.8500 6.94100
[moleculetype]
; name nrexcl
SO4 1
[atoms]
;nr type resnr residu atom cgnr charge
1 OSO4 1 SO4 O1 1 -0.65 24.01565
2 OSO4 1 SO4 O2 1 -0.65 24.01565
3 OSO4 1 SO4 O3 1 -0.65 24.01565
4 OSO4 1 SO4 O4 1 -0.65 24.01565
5 SSO4 1 SO4 S5 1 0.9 0.0
[constraints]
;i j funct dist
; dist_OX=0.149; dist_XX=2*sqrt(2/3)*dist_OX
1 2 1 0.243316
1 3 1 0.243316
1 4 1 0.243316
2 3 1 0.243316
2 4 1 0.243316
3 4 1 0.243316
[exclusions]
1 2 3 4 5
2 1 3 4 5
3 1 2 4 5
4 1 2 3 5
5 1 2 3 4
[ virtual_sitesn ]
; Site funct from
5 1 1 2 3 4
[system]
water_sal
[molecules]
water 555
Na 1
Cl 1
Mg 1
Ca 1
K 1
Li 1
SO4 1
“”"