Date: Fri Jan 06 2017 - 12:52:40 CST

Dear VMD users,

I would like to use FFTK to determine the CHARMM parameters for diazonium-modified tyrosine. I am setting up the problem using a fragment approach, where I have the tyrosine residue and diazosulfonic-acid fragment. The .mol2 and .str files from paramchem are available here:

I've obtained the water interaction energies from Gaussian for the entire modified residue as well as only for the diazosulfonic-acid fragment alone. The question now is from which of this should I run the charge optimisations and which atoms ought to be constrained? From the paramchem results, the highest penalties are in the region around the -N=N- atoms. Should I then constrain the atoms such that only adjacent atoms are optimised, i.e., -C-N=N-C-?

Best Regards,

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