On 4/2/19 7:52 AM, Alex Lian wrote: > I need some help about the single mutant script. The following is a > warning message I found in the log file. > > generat_607W> Cannot find params in params file: >               CHARMM atoms :  C UNDF >               IUPAC atoms  :  C N >               Atom indices :      900     902 >               Residues     :  GLU PTR

It's a little difficult to tell out of context, but it looks like your PTR residue type (whatever that is) is missing bond parameters.

Ben Webb, Modeller Caretaker