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<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006>Hi,</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006>I want to add both
sodium and potassium to a protein solution. But there is always error
information about potassium after I used genion to add K(K+) and set right no of
molecules at the bottom of .top file:</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006><STRONG>No such
moleculetype K (or K+)</STRONG></SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006>no matter I use K or
K+ as potassium name and no matter I used g43a1 or OPLS-AA ff.
</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006>By the way, I
used v3.3 and selected gromos 43a1 force fields. I have searched the
mailing list and found some confusing information. For example, somebody said
the 43a1 can recognize potassium, but someone else said it can
not and suggested to use OPLS-AA instead. So can anybody who have
experiences give an authoritative explanation and solution
for using potassium?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006>Further, is there
any reference which provides a general description for all force fieds in Gmx
v3.3, which is expected to be more detailed than something showing in
brackets after the ff names when using the command pdb2gmx, so
that users can know their advantages and disadvantages and select a suitable one
according to different aims?</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2><SPAN
class=993301101-23112006></SPAN></FONT> </DIV>
<DIV><FONT face=Arial size=2><SPAN class=993301101-23112006>Thanks in
advance</SPAN></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV align=left>
<DIV align=left><FONT face="Times New Roman" size=4>Zhongqiao Hu</FONT></DIV>
<DIV align=left><FONT face=Arial size=2></FONT> </DIV>
<DIV align=left><FONT face="Times New Roman">Lab E5-04-27</FONT></DIV>
<DIV align=left>
<DIV align=left><FONT face="Times New Roman">Tel: 65161946(O)</FONT></DIV></DIV>
<DIV align=left><FONT face="Times New Roman">Department of Chemical and
Biomolecular Engineering</FONT></DIV>
<DIV align=left><FONT face="Times New Roman">National University of
Singapore</FONT></DIV>
<DIV align=left><FONT face="Times New Roman">117576, Singapore</FONT></DIV>
<DIV align=left><FONT face="Times New Roman"></FONT> </DIV></DIV>
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