[gmx-users] errors with charmm36 ?

Albert mailmd2011 at gmail.com
Tue Jan 14 17:47:42 CET 2014

It is good to know that the c36 and CGenFF is actively update. I just 
noticed that this new version c36 no longer contains classic TII3P water 

  1: TIP3P   TIP 3-point, recommended, by default uses CHARMM TIP3 with 
LJ on H
  2: TIP4P   TIP 4-point
  3: TIP5P   TIP 5-point
  4: SPC     simple point charge
  5: SPC/E   extended simple point charge
  6: None

So in priciple, we have to use CHARMM TIP3P model, is it correct?

I am always wondering, would it be better if there is a tool that could 
convert the output from paramchem websever into a "single" ligand.itp 
file? The parachem website can export the results including all known 
information from CGenFF related to target ligand. In such compelte 
output file, it contains all necessary information for a ligand 
parameters and toplogy....

thank you very much


On 01/14/2014 05:14 PM, Justin Lemkul wrote:
> I think it is probably worth emphasizing a point I have made 
> previously, because I suspect there may be some confusion among the 
> users out there.  The tarball that can be downloaded from the website 
> contains updated parameters for CHARMM36 lipids ONLY.  The parameters 
> in that distribution have outdated CHARMM22+CMAP parameters for 
> proteins and CHARMM27 for nucleic acids (i.e. the files distributed as 
> "charmm27.ff" in Gromacs).  Users should not be led to believe that 
> this tarball contains the full CHARMM36 force field, which is a 
> different entity, available only from the MacKerell lab (note we will 
> be uploading a new tarball soon that has updated parameters for CGenFF 
> 2b8).
> -Justin 

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