Hi everybody,

Working on Discovery Studio 2.1, I met an abnormal case. While I run a molecular dynamic simulation with CHARMm (using Standard Dynamic Cascade Protocol), the solvated system without constraint remains frozen, whatever the temperature (300 to 500K). Whereas with charmm22, the system moves normally. I feel that there is some strong harmonic restraint applied across the system with CHARMm.

Actually, I must use CHARMm forcefield because my molecular system to simulate contains several molecules like carbohydrate unrecognized by academics charmm forcefields available at my lab (charmm 19, 22 and 27).

This is a configuration problem? Edit -> Preferences -> Forcefield -> CHARMm ??

Has anyone ever encountered this problem?

Best regards,

Johann