You may be wondering which forcefield to use if your protein has modified amino acid residues containing lipid tail linkers. For example residues that have undergone palmitoylation, myristoylation, farnesylation or geranylation.

The good news is that the charmm36 forcefield has residue templates for these types of amino acids . 

LYSM          Lysine-myristate

GLYM         Glycine-myristate

CYSP        Cysteine-Palmitate

CYSF        Cysteine-Farnesyl

CYSG        Cysteine-Geranyl

If you want to see what other types can be found in this forcefield you can always explore the charmm36 residue topology file found in your server installation under: \\apps\\scitegic\\dscore\\server\\share\\forcefield\\charmm36\\top_all36_accelrys.rtf file (where is the location of your Discovery Studio server installation).

As a reminder, the charmm36 forcefield supports additional functional forms that are not suitable for the client typing method. To support these moieties, the Assign Forcefield protocol works by matching each residue to its template structurally. It also recognizes where residue patches need to be applied to match the structure and applies them automatically. The assigned forcefield types are saved in the molecule DSV format so that they are automatically used in subsequent simulation calculations.