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    On 22/11/2011 10:08 PM, ifat shub wrote:
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        <div>Hi,</div>
        <div>I am running simulations using implicit solvent. I am using
          the pbc = no option in my mdp file, however, I see it the .gro
          file that gromacs is creating a box for the system.What is the
          effect&nbsp;of the box in&nbsp;implicit solvent simulations?</div>
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    None, if pbc = no. When writing a .gro file some data has to go into
    the space the format allows for the box. However the .mdp file
    controls whether that is significant. Later on when using analysis
    tools, some of the analyses might erroneously use that box if you
    don't give suitable instructions not to.<br>
    <br>
    Mark<br>
    <br>
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        <div>&nbsp;</div>
        <div>This is&nbsp;the mdp file&nbsp;that I am using:</div>
        <div><span lang="EN">
            <p>------run.mdp------</p>
            <p>integrator = md</p>
            <p>nsteps = 20000</p>
            <p>dt = 0.001</p>
            <p>implicit_solvent = GBSA</p>
            <p>pbc = no</p>
            <p>nstlist = 0</p>
            <p>ns_type = simple</p>
            <p>rlist = 0</p>
            <p>rgbradii = 0</p>
            <p>coulombtype = Cut-off</p>
            <p>rcoulomb = 0</p>
            <p>vdwtype = Cut-off</p>
            <p>rvdw = 0</p>
            <p>tcoupl = v-rescale</p>
            <p>tc_grps = system</p>
            <p>tau_t = 0.1 </p>
            <p>ref_t = 1000</p>
            <p>energygrps = Protein_chain_A Protein_chain_C
              Protein_chain_E Protein_chain_G Protein_chain_I
              Protein_chain_K</p>
            <p>gen_vel = yes</p>
            <p>gen_temp = 1000</p>
            <p>ld_seed = -1</p>
            <p>gen_seed = -1</p>
            <p>nstxout = 1</p>
            <p>nstvout = 1</p>
            <p>nstxtcout = 1</p>
            <p>nstenergy = 1</p>
            <p>------------------</p>
          </span></div>
        <div>Thanks,</div>
        <div>Ifat</div>
        <div>&nbsp;</div>
        <div>M.Sc. Student<br>
          Bar Ilan University<br>
          Ramat Gan<br>
          Israel<br>
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