Hi,
I am trying to perform a QM/MM simulation of my protein-ligand complex, I
took the last structure as reference complex after performing classical
simulation for QM-MM simulation. The ligand is cellotriose.
This is my QMM_minimization settings:
QM_MM minimization of the whole system
&cntrl
imin = 1,
maxcyc=2000, ncyc=500,
ntc=1,ntf=1, (tried minimization even after removing ntc and ntf parameters)
ntb=1, cut=12,
ifqnt=1
&end
&qmmm
qmmask='.2138-2143,7734-7740,8089-8154,27938-27940,30275-30277,27860-27862,19376-19378,27785-27787,27725-27727,30701-30703,30635-30637,30803-30805,28574-28576'
qmcharge=-1,
qm_theory='PM3',
qmcut=20.0,
writepdb=1
&end
I am getting the scf convergence error:
NSTEP ENERGY RMS GMAX NAME NUMBER
1 -2.3391E+05 1.4515E+01 1.2564E+02 C 5807
BOND = 1607.7229 ANGLE = 4323.1875 DIHED =
5722.6413
VDWAALS = 27085.4285 EEL = -293394.1219 HBOND =
0.0000
1-4 VDW = 1888.7780 1-4 EEL = 20436.3296 RESTRAINT =
0.0000
PM3ESCF = -1575.1372
QMMM: WARNING!
QMMM: Unable to achieve self consistency to the tolerances specified
QMMM: No convergence in SCF after 1000 steps.
QMMM: Job will continue with unconverged SCF. Warning energies
QMMM: and forces for this step will not be accurate.
QMMM: E = -0.3375E+07 DeltaE = -0.5322E+00 DeltaP = 0.3390E-01
QMMM: Smallest DeltaE = -0.1711E+00 DeltaP = 0.5432E-01 Step = 107
QMMM: WARNING!
QMMM: Unable to achieve self consistency to the tolerances specified
QMMM: No convergence in SCF after 1000 steps.
QMMM: Job will continue with unconverged SCF. Warning energies
QMMM: and forces for this step will not be accurate.
QMMM: E = -0.3375E+07 DeltaE = -0.8071E+02 DeltaP = 0.1957E+00
QMMM: Smallest DeltaE = -0.2609E-02 DeltaP = 0.2574E-01 Step = 407
NSTEP ENERGY RMS GMAX NAME NUMBER
50 -2.7688E+05 4.9455E+00 1.4093E+03 CD 7737
BOND = 17243.1554 ANGLE = 1440.2217 DIHED =
5057.5828
VDWAALS = 23042.9878 EEL = -344395.1654 HBOND =
0.0000
1-4 VDW = 1689.8181 1-4 EEL = 20450.3034 RESTRAINT =
0.0000
PM3ESCF = -1408.1636
What could be wrong with my system? Is it the starting conformation or the
usage wrong hamiltonian ? Is it wrong choice of the of cutting the QM and
MM atoms?
I have provided a link to my files here:
https://drive.google.com/open?id=0B6ehLXK0eP7saWdHeDg3dE5TSnc
Could anybody please provide some help in solving this problem.?
--
*Best Regards*
BM
_______________________________________________
AMBER mailing list
AMBER.ambermd.org
http://lists.ambermd.org/mailman/listinfo/amber
Received on Tue Jun 28 2016 - 02:30:02 PDT
