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    On 2/06/2012 7:10 PM, xi zhao wrote:
    <blockquote
      cite="mid:1338628235.86730.YahooMailClassic@web15103.mail.cnb.yahoo.com"
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              <div>Dear&nbsp;gmx-users:</div>
              <div>When I try to simulation a system: protein + ligand
                molecule using the Implicit Solvent method. the
                parameters of Ligand were produced by acpype, but when
                grompped, the appeared" </div>
              <div>"&nbsp;Velocities were taken from a Maxwell distribution
                at 300 K</div>
              <div>GB parameter(s) missing or negative for atom type 'o'</div>
              <div>GB parameter(s) missing or negative for atom type
                'os'</div>
              <div>GB parameter(s) missing or negative for atom type 'c'</div>
              <div>GB parameter(s) missing or negative for atom type
                'c3'</div>
              <div>GB parameter(s) missing or negative for atom type
                'hc'</div>
              <div>GB parameter(s) missing or negative for atom type
                'h1'</div>
              <div>-------------------------------------------------------<br>
                Program grompp_d, VERSION 4.5.3<br>
                Source code file: grompp.c, line: 1123</div>
              <div>Fatal error:<br>
                Can't do GB electrostatics; the implicit_genborn_params
                section of the forcefield is missing parameters for 6
                atomtypes or they might be negative."</div>
              <div>when I modified "<a moz-do-not-send="true"
                  class="plink"
href="http://cn.webmessenger.yahoo.com/index.php?t=1&amp;to=eWlkPXpoYW94aWl0YzIwMDI-&amp;sig=703fa929658518b2720b087c59cd85f2dabf8844"
                  rel="nofollow" target="_blank"><img
                    moz-do-not-send="true" class="pimg" alt="4"
                    src="http://opi.yahoo.com/online?u=zhaoxiitc2002&amp;t=4&amp;l=cn"
                    border="0"></a>amber99sbr.ff/gbsa.itp by adding the
                atomtype of ligand, the problem is still the same, </div>
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    <br>
    Then you apparently didn't add them correctly. See manual section
    5.3.5 and second paragraph of <a
href="http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field">http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field</a><br>
    <br>
    Mark<br>
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