[gmx-users] Two different force field use in one simulation?

[Mijiddorj Batsaikhan]

Dear Justin,

Thank you very much. Can I use 2 different force fields in same simulation?
It means charmm27 for the DOPI and charmm36 for other groups.


Best regards,

Mijiddorj



> Dear gmx users,
>
> I would like to simulate a system that consists of 2 different membranes
> and protein molecule. DOPI membrane model could not find from Charmm-gui
> ,embrane builder's models. I built the system DMPI membrane instead of
> DOPI. Then I modified DMPIs to DOPIs, and got charmm27 force field
> parameters using swissparam. Charmm-gui give me charmm36 parameters. I
want
> to use charmm27 for only DOPI. I have some questions.
>
> (1) Is these type of modification possible to the simulations?
>
> (2)  How can I convert charmm27 to charmm36 parameter?
>

You can't just convert one force field to another.  CHARMM36 is superior to
the
outdated CHARMM27 for lipids, so it is a much better force field model for
doing
current simulations.

-Justin

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