Hi,

I am new to charmm and would like to ask about the following. I want to patch a tyrosine residue in a protein into dianionic phospotyrosine using charmm 27 in Accelrys. I can do this using str stream (patch TP2) using the command line using charmm 27 topology and parameter files together with phosphotyrosine str file. However when I tried to solvate the protein in Discovery studio, it can't type the PTYR residue using charmm 27 as the template for this residue is not found. Please tell me how to either modify the RTF file or PRM file to type this residue correctly. I need detailed explaintation. N.B CharMm has PTR residue in its file but its is monionic and need also to know how to deal with this problem i want to type using CHARMm. Please help me out