I would like to parameterize a non-standard residue derived from sulfonic acid and tyrosine. I've attached the corresponding .mol2 file. I've used paramchem with the capped amino acid but the penalties are way off the charts. I've attached the .str file as well.
May I know whether there is a better method to cobble together the parameters? Should I separate the parameterization of the diazonium from that of tyrosine and would that give me better results?