[gmx-users] DNA orientation restraint

[仝督读]

Hi everyone,

I am doing a DNA simulation in a long simulation box (the lengthen of z is
much larger than x and y). So I want to constrain the DNA molecule lying
along the z axis. But I don't know how to realize this in GROMACS.

Actually I notice there is orientation restraints in 4.3.5 of GMX Manual.
But the orientation value is set to be observables of NMR experiments, such
as this example:
; ai aj type exp. label alpha
31 32 1 1 3 3