Missing N-term patch dihedral CHARMM36m port

User discussions
1

GROMACS version: 2019.4
GROMACS modification: No

Dear all
I’m using the last GROMACS port of CHARMM36m for my system (charmm36-jul2020.ff). I found a small issue trying to use the [NH2] capping patch for the N-terminal of my peptide. It seems that a dihedral is missing since in my peptide the second residue from the N-terminal is a proline, so with a different atom type for the peptide nitrogen (N) than the peptide nitrogen of other residues (NH1). Since this dihedral is present:

 NH2      CT1        C      NH1     9     0.000000     0.000000     1

My guess is that to solve my issue it could be enough to add a dihedral as:

 NH2      CT1        C        N     9     0.000000     0.000000     1

Thanks for your suggestions and help.
Best regards

2

That would be a reasonable parameter assignment by analogy, yes.