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<DIV><FONT face=Arial color=#000000 size=2>Dear Gromacs users,</FONT></DIV>
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<DIV><FONT face=Arial size=2>I would like so simulate a protein with phosphorylated amino acids with Gromacs 4.5.3. To do so, I got the "ffG43a1p" forcefield available from the user contributions section (subsection force fields) and adapted the parameters given there to Gromos53a6. </FONT></DIV>
<DIV><FONT face=Arial size=2>The problem now is that they introduced a new atom type called "OP", which I have to add to the atomtypes.atp of my modified force field. I already read about problems of a modified atomtypes.atp here in the mailing list, but I assumed the problems were sorted out with version 4.5.3.</FONT></DIV>
<DIV><FONT face=Arial size=2>But if I add OP to the atom list, pdb2gmx works fine, but grompp is raising the error</FONT></DIV>
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<DIV><FONT face=Arial size=2>Program grompp, VERSION 4.5.3.</FONT></DIV>
<DIV><FONT face=Arial size=2>Source code file: toppush.c, line: 629</FONT></DIV>
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<DIV><FONT face=Arial size=2>Fatal error:</FONT></DIV>
<DIV><FONT face=Arial size=2>Unknown atomtype CMET</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>which is quite strange because "CMET" isn't appearing in any file I'm using. When I remove OP from the atom list, pdb2gmx is of course raising an error, so I'm a bit stuck here...</FONT></DIV>
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<DIV><FONT face=Arial size=2>To cut a long story short: Is there any way to introduce a new atom type to atomtypes.atp or do I have to parameterize the phosphorylated residues with already presend atom types? </FONT> </DIV>
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<DIV><SPAN lang=DE><FONT face=Arial size=2>Thank you in advance,</FONT></SPAN></DIV>
<DIV><SPAN lang=DE><FONT face=Arial size=2>Felix Rausch</FONT></DIV>
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