On Fri, Aug 01, 2025, Simona Saporiti via AMBER wrote:
>I am performing a simulation using ff19SB force field.
>When using tleap a fatal error occurs about the atom OXT of CYM.
>After some testing I figured out that CCYM (CYM C-terminal) is not available for both ff19SB and ff14Sb (I didn't test any other ff).
>Do you know if parameters for CCYM exist anywhere?
The Stony Brook people can answer better than I can, but here is what is
probably a good start: look at the differences between CYM and CYX in the
amino19.lib file in the dat/leap/lib folder. Then try to use those same
differences to convert CCYX to CCYM in aminoct12.lib.
You don't have to worry about CMAP terms, since (I hope I am correct here!)
ff19SB doesn't use CMAP for the N- and C-terminal residues.
Better answers may be forthcoming soon on the this list.
...dac
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Received on Sat Aug 02 2025 - 14:30:02 PDT
