[gmx-users] Equilibration

[farial tavakoli]

 blockquote, div.yahoo_quoted { margin-left: 0 !important; border-left:1px #715FFA solid !important; padding-left:1ex !important; background-color:white !important; }      HiI am a new GROMACS user and i am trying to run a simulation on 4LY1 protein and my designed drug to check their interaction I used gromos 43a1 force field and when i performed equilibration with NVT.mdp file , I faced this error: step 1: One or more water molecules can not be settled. Check for bad contacts and/or reduce the timestep if appropriateI really appropriate if anybody can help meThanks alotFarialI typed this command  gmx grompp -f nvt.mdp -c em.gro -p topol.top -n index.ndx -o nvt.tpr
gmx mdrun -deffnm nvtThe nvt. Mdp file which i used:
title       = Protein-ligand complex NVT equilibration 
define      = -DPOSRES -DPOSRES_LIG ; position restrain the protein and ligand
integrator  = md        ; leap-frog integrator
nsteps      = 50000     ; 2 * 50000 = 100 ps
dt          = 0.002     ; 2 fs
; Output control
nstxout     = 500       ; save coordinates every 1.0 ps
nstvout     = 500       ; save velocities every 1.0 ps
nstenergy   = 500       ; save energies every 1.0 ps
nstlog      = 500       ; update log file every 1.0 ps
energygrps  = Protein DRG
; Bond parameters
continuation    = no            ; first dynamics run
constraint_algorithm = lincs    ; holonomic constraints 
constraints     = all-bonds     ; all bonds (even heavy atom-H bonds) constrained
lincs_iter      = 1             ; accuracy of LINCS
lincs_order     = 4             ; also related to accuracy
; Neighborsearching
cutoff-scheme   = Verlet
ns_type         = grid      ; search neighboring grid cells
nstlist         = 10        ; 20 fs, largely irrelevant with Verlet
rcoulomb        = 1.4       ; short-range electrostatic cutoff (in nm)
rvdw            = 1.4       ; short-range van der Waals cutoff (in nm)
; Electrostatics
coulombtype     = PME       ; Particle Mesh Ewald for long-range electrostatics
pme_order       = 4         ; cubic interpolation
fourierspacing  = 0.16      ; grid spacing for FFT
; Temperature coupling
tcoupl      = V-rescale                     ; modified Berendsen thermostat
tc-grps     = Protein_DRG Water_and_ions    ; two coupling groups - more accurate
tau_t       = 0.1   0.1                     ; time constant, in ps
ref_t       = 300   300                     ; reference temperature, one for each group, in K
; Pressure coupling
pcoupl      = no        ; no pressure coupling in NVT
; Periodic boundary conditions
pbc         = xyz       ; 3-D PBC
; Dispersion correction
DispCorr    = EnerPres  ; account for cut-off vdW scheme
; Velocity generation
gen_vel     = yes       ; assign velocities from Maxwell distribution
gen_temp    = 300       ; temperature for Maxwell distribution
gen_seed    = -1        ; generate a random seed

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