[gmx-users] distance constrain of two groups

[Ming Tang]

Dear all,

After energy minimization, I want to equilibrate my triple helix using NPT, but need to keep its general shape, as I want to study the load-deformation relationship including the triple helix unfolding stage. During the equilibration, I want to fix the distance between the centre of mass of two group atoms  along the vector connecting the two groups.
Could anybody tell me how can I do this？

Thanks in advance.