Dear Prof. Venable,

Thank you so much for your reply.
I tried copying the following PRES GLYQ parameters from the C22 files into C27 file:

NTL CC 215.00 1.51 ! add by Simon Berneche

NH2 CT2 C 50.000 107.00 ! ALLOW PEP POL ARO ALI
! Simon Berneche 94/11/22 for PRES GLYQ for melittin from NH1 CT2 C 50.000 107.00

NH1 C CT2 NH2 0.6000 1 0.00 ! ALLOW PEP
! Simon Berneche for PRES GLYQ for melittin from NH1 C CT2 NH1 0.6000 1 0.00
O C CT2 NH2 0.0000 1 0.00 ! ALLOW PEP
! Simon Berneche for PRES GLYQ for melittin from O C CT2 NH1 0.0000 1 0.00
HC NH2 CT2 C 0.0000 1 0.00 ! ALLOW PEP
! Simon Berneche 94/11/22 for PRES GLYQ for melittin


in the parameter file and PRES GLYQ in the topology file. Still it gives me one missing parameter that is an improper dihedral angle: CC CT1 NTL O

What can I do about this? I am still not very sure of copying the parameters like this. Is this alright?

regards,
MzZt.