<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div style="RIGHT: auto"><SPAN style="RIGHT: auto">Hi Justin,</SPAN></div>
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<div style="RIGHT: auto"><SPAN style="RIGHT: auto">(1) None of the ligands have 31 atoms - FAD has 86 atoms and MHF has 54 atoms. The error msg. does not show any specific mismatching.</SPAN></div>
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<div style="RIGHT: auto"><SPAN style="RIGHT: auto">(2) I forgot to mention that I have increased the number of the atoms on the top (2nd line) of the gro file after adding the 2 ligands.<VAR id=yui-ie-cursor></VAR></SPAN></div>
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<div style="RIGHT: auto"><SPAN style="RIGHT: auto">Samrat </SPAN></div>
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<DIV style="BORDER-BOTTOM: #ccc 1px solid; BORDER-LEFT: #ccc 1px solid; PADDING-BOTTOM: 0px; LINE-HEIGHT: 0; MARGIN: 5px 0px; PADDING-LEFT: 0px; PADDING-RIGHT: 0px; HEIGHT: 0px; FONT-SIZE: 0px; BORDER-TOP: #ccc 1px solid; BORDER-RIGHT: #ccc 1px solid; PADDING-TOP: 0px" class=hr contentEditable=false readonly="true"></DIV><B><SPAN style="FONT-WEIGHT: bold">From:</SPAN></B> Justin A. Lemkul <jalemkul@vt.edu><BR><B><SPAN style="FONT-WEIGHT: bold">To:</SPAN></B> Samrat Pal <psamrat10@yahoo.com>; Discussion list for GROMACS users <gmx-users@gromacs.org><BR><B><SPAN style="FONT-WEIGHT: bold">Sent:</SPAN></B> Friday, October 21, 2011 8:49 AM<BR><B><SPAN style="FONT-WEIGHT: bold">Subject:</SPAN></B> Re: [gmx-users] mismatch in coordinate and topology<BR></FONT><BR><BR><BR>Samrat Pal wrote:<BR>> Hi All,<BR>> I am trying to minimize the chryptochrome structure that has one FAD and one MHF ligand bound to
it.<BR>> Following are the steps that I performed ----<BR>> (1) Created the protein coordinate(gro) file using pdb2gmx command and choosing GROMOS43a1 force-field<BR>> (2) Created the FAD and MHF topology and coordinate files using PRODRG where I have chosen<BR>> a) no chirality, b) full charge and (c) no minimization. /I have not seen any option for choosing force-field in the server/. (3) I have taken the corresponding coordinate and topology files from that server, appended the coordinates of both the ligands in the gro file of the protein (before the box vector i.e. the last line), and also included the ligand topology files in the topol.top file after "posre.itp" and before "spc.itp"accordingly.<BR><BR>Regarding (2) and (3) - the output of the PRODRG server will likely give poor results. See the paper linked from http://www.gromacs.org/Downloads/Related_Software/PRODRG#Tips.<BR><BR>> (4) I have also
added two lines in the [molecules] section like,<BR>> FAD 1<BR>> MHF 1<BR>> (5) Then I have created a cubic box where I have taken the coordinate and solvated the protein+ligands coordinate with spc water model using genbox.<BR>> <BR><BR>A dodecahedral box is likely going to be more efficient, but this is not relevant to the problem at hand.<BR><BR>> (6) Then I tried to create the em.tpr file from em.mdp file using grompp command.<BR>> I got the following error message --- number of atoms in the coordinate file does not match with topology file where topology file has 31 missing atoms according to the numbers shown in the error message.<BR>> <BR><BR>OK, so do any of your molecules consist of 31 atoms? Do you get any notes about non-matching names?<BR><BR>> I have checked the topology file after solvation and it is updated having the last line of the file with SOL
34741.<BR>> I have been using gromacs for few months and I have successfully simulated systems with ligands before. Could anybody please tell me where I am doing wrong? <BR><BR>Did you properly increment the number of atoms in the coordinate file after adding your ligands?<BR><BR>-Justin<BR><BR>-- ========================================<BR><BR>Justin A. Lemkul<BR>Ph.D. Candidate<BR>ICTAS Doctoral Scholar<BR>MILES-IGERT Trainee<BR>Department of Biochemistry<BR>Virginia Tech<BR>Blacksburg, VA<BR>jalemkul[at]vt.edu | (540) 231-9080<BR>http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin<BR><BR>========================================<BR><BR><BR></DIV></DIV></div></body></html>