<pre><br></pre><pre>>Stanislav Bobritsky wrote:<br>>><i> Hello dear gromacs users!<br></i>><i><span style="font-style: italic;">></span> I`m trying to do targeted MD. I have two protein conformations which are
<br><br></i>><i><span style="font-style: italic;">></span> different from each other by one loop position. I need to force <br></i>><i><span style="font-style: italic;">></span> conformation A to B.<br></i>>
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<span style="font-style: italic;">></span> It was following commands executed:<br></i>><i><span style="font-style: italic;">></span> <br></i>><i><span style="font-style: italic;">></span> grompp -Ó box.gro
-f <br>md.mdp -r conf1.pdb -rb conf2.pdb -p topol.top -o <br></i>><i><span style="font-style: italic;">></span> transformer.tpr<br></i>><i><span style="font-style: italic;">></span> <br></i>><i><span style="font-style: italic;">
></span> mdrun -s transformer.tpr -o -x -c -e -g -v<br></i>><i><span style="font-style: italic;">></span> <br></i>><i><span style="font-style: italic;">></span> But it can be viewed from traj.xtc that conformation didn`t change.
<br><br></i>><i><span style="font-style: italic;">></span> Protein just spins (with speed increasing), and desired loop does not move.<br></i>><i><span style="font-style: italic;">></span> <br></i>><i><span style="font-style: italic;">
></span> What can I do to fix it?<br></i>><br>>What's in your .mdp file?<br>><br>>Mark</pre>.mdp file contains following:<br><br>title = prot
<br>cpp = cpp<br>define = -DFLEX_SPC<br><br>integrator = md
<br>tinit = 0<br>dt = 0.001<br>nsteps = 1000000<br>init_step = 0
<br>comm-mode = Linear<br>nstcomm = 1<br>comm-grps =
<br>bd-fric = 0<br>ld-seed = 1993<br>emtol = 1000.0<br>emstep = 0.001<br>niter = 20<br>fcstep = 0
<br>nstcgsteep = 1000<br>nbfgscorr = 10<br>nstxout = 1000<br>nstvout = 2000<br>nstfout = 2000<br>nstcheckpoint = 10000<br>nstlog = 100
<br>nstenergy = 1000<br>nstxtcout = 1000<br>xtc-precision = 1000<br>xtc-grps = protein ;SOL UNK CL-<br>energygrps = protein ;SOL UNK CL-<br>nstlist = 10
<br>ns_type = Grid<br>pbc = xyz<br>rlist = 0.9<br>domain-decomposition = no<br>coulombtype = PME
<br>rcoulomb-switch = 0<br>rcoulomb = 0.9<br>epsilon_r = 1<br>epsilon_rf = 1<br>vdw-type = Cut-off<br>rvdw-switch = 0<br>rvdw =
1.4<br>DispCorr = EnerPres
<br>table-extension = 1<br>energygrp_table = <br>fourierspacing =
0.12<br>fourier_nx = 0<br>fourier_ny = 0<br>fourier_nz = 0<br>pme_order = 4
<br>ewald_rtol = 1e-5<br>ewald_geometry = 3d<br>epsilon_surface = 0<br>optimize_fft = yes<br>gb_algorithm = Still<br>nstgbradii = 1<br>rgbradii = 2
<br>gb_saltconc = 0<br>implicit_solvent = No
<br>tcoupl = berendsen<br>tc-grps = protein ; sol CL- UNK<br>tau_t = 0.1 ; 0.1 0.1 0.1<br>ref_t = 298 ; 298 298 298<br>Pcoupl = no
<br>Pcoupltype = Isotropic<br>tau_p = 1.0<br>compressibility = 4.5e-5<br>ref_p = 1.0 1.0 1.0<br>andersen_seed = 815131<br><br>gen-vel = no
<br>gen-temp = 298<br>gen-seed = 173529<br>constraints = all-bonds<br>constraint-algorithm = Shake
<br>unconstrained-start = yes<br>Shake-SOR = no<br>shake-tol = 1e-04<br>lincs-order = 4<br>lincs-iter = 2<br>lincs-warnangle = 60
<br>morse = no<br>energygrp_excl =
<br>disre = No<br>disre-weighting = Conservative
<br>disre-mixed = no<br>disre-fc = 1000<br>disre-tau = 0<br>nstdisreout = 100<br>orire = no<br>orire-fc = 0<br>orire-tau = 0
<br>orire-fitgrp = <br>nstorireout = 100<br>dihre = No<br>dihre-fc = 1000
<br>dihre-tau = 0<br>nstdihreout = 100<br><br>free-energy = no<br>init-lambda = 0
<br>delta-lambda = 0<br>sc-alpha = 0<br>sc-power = 0<br>sc-sigma = 0.3<br><br><span><span>Stanislav Bobritsky, <br>ChemBio Center, Taras Shevchenko National University, Kiev, Ukraine.
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