[gmx-users] '+' and '-' sign in rtp file

[Chandan Choudhury]

I had a simple query regarding the rtp file . What does the '+' and '-' sign
indicates in the following dihedral inforamtion:

 [ dihedrals ]
    CA     C    +N    +H    backbone_prop_1
     O     C    +N    +H    backbone_prop_2
    -C     N    CA    CB    backbone_prop_3
    -C     N    CA     C    backbone_prop_4
    CA     C    +N   +CA    backbone_prop_1
     O     C    +N   +CA    backbone_prop_1

Also, I cant understand the what is 'X' here in ffamberbon.itp:

X   C   C   X     3    30.33400     0.00000   -30.33400     0.00000
0.00000     0.00000     ; new99
X   C   O   X     3    23.43040     0.00000   -23.43040     0.00000
0.00000     0.00000     ; new99
X   C   OS  X     3    22.59360     0.00000   -22.59360     0.00000
0.00000     0.00000     ; new99


Chandan

--
Chandan kumar Choudhury
NCL, Pune
INDIA
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