[Xplor-nih] adding alcohol C-terminal capping

[Ma, Lixin]

We have trouble adding C-terminal CH2OH group on the last residue Thr. 
We made a presidue CTOH as following. However it didn't work, we had
error msgs such as missing improper parameters, improper energy constant
missing, target improper value missing. What did we miss in this
topology file? or do we have another way to get the c terminal capped
on? 
We would appreciate very much if you can help us on this.
 
  

presidue CTOH                  ! C-terminal for all, CH2OH at end "* -
CTOH" 
   delete  atom -O   type=O   charge=-0.48 end
  group 
   modify atom -C type=CT       charge= 0.08 end
   add atom -H1 type=HA  charge= 0.10 end
   add  atom -H2 type=HA  charge= 0.10 end
  group
   add atom -OH type=OH charge=-0.68 end
   add atom -H3  type=H   charge= 0.40 end
  add bond -C -H1
  add bond -C -H2
  add bond -C -OH
  add bond -OH -H3
  add angle -CA -C  -OH
  add angle -H1 -C  -H2
  add angle -H3  -OH -C
  add angle -H1 -C  -OH
  add angle -H2 -C  -OH
  add improper H1 H2 CA OH  !stereo CH2
  add dihedral OH  C  CA  CB
end


Lixin Ma

mal at health.missouri.edu

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