CHARMM Development Project Forums User Discussion & Questions Minimization, Normal modes, Monte Carlo,... QM/MM minimization error

Dear all,

The following error was obtained for the system of protein with two ligands when running the minimization step of the QM/MM.

***** LEVEL -1 WARNING FROM *****
***** shake already active and may affect fixed atoms
******************************************
BOMLEV ( -1) IS REACHED - TERMINATING. WRNLEV IS 5

The respective .inp and .out files are attached here.Appreciate if you can give a help on this.

Thanks

One possibility is that the PSF was saved with CONS FIX active for some atoms. If so, adding the following line after reading the .psf file should cure the problem--

CONS FIX SELE NONE END

I did what you suggested but it still giving the same problem. is there any other possibility that I can try?.

Thanks.

Maybe use an atom selection to limit the scope of the SHAKE command