As a new user of NAMD, I am seeking assistance regarding a specific task. I intend to pull a LIGAND from outside to the center of a lipid using NAMD. To achieve this, I have utilized the colvar module with the distance option to measure the separation between two distinct groups: the center of mass of LIGAND and as well the center of mass molecules in the center of the lipid.
In my attempts to exert control over this process, I have employed a harmonic constraint. However, I have encountered an issue where the LIGAND exhibits movement in multiple directions, contrary to my intention of restricting its motion to a single axis, similar to the pull code in GROMACS.
Thus, I am inquiring whether there exists a method within NAMD to confine the axis along which the distance between these two groups decreases.