mass  NHHE  16.02270 ! extended atom nitrogen with two hydrogen

residue NHH
  group
    atom N   type=NHHE  charge=0.00  end
end


presidue NHHL { link for all amino acids except proline }
  add bond -C +N

  add angle -CA -C +N
  add angle -O  -C +N

  add improper  -C -CA +N -O  {planar -C}
end


presidue NHHP  { link for proline }
 add bond -C +N

 add angle -CA -C +N
 add angle -O  -C +N

 add dihedral  -N -CA -C +N

 add improper  -C -CA +N -O  {planar -C}
end


residue ACE
  group
    atom CA   type=CH3E  charge=0.00  end
    atom C    type=C     charge=0.00  end
    atom O    type=O     charge=0.00  end

  bond C   CA
  bond C   O
end

presidue ACEL { link for all amino acids except proline }
  add bond -C +N

  add angle -CA -C +N
  add angle -O  -C +N
  add angle -C  +N +CA
  add angle -C  +N +H

  add dihedral  -C +N +CA +C
  add dihedral  -CA -C +N +CA

  add improper  -C -CA +N -O  {planar -C}
  add improper  +N -C +CA +H  {planar +N}
end

presidue ACEP { link for proline }
 add bond -C +N

 add angle -CA -C +N
 add angle -O  -C +N
 add angle -C  +N +CA
 add angle -C  +N +CD

 add dihedral  -C +N +CA +C
 add dihedral  -CA -C +N +CA

 add improper  -C -CA +N -O  {planar -C}
 add improper  +N +CA +CD -C  {planar +N}
end