Hi Subhani, if phenix.refine recognizes an atom as siting on special position then it will automatically apply proper constraints to its motions. Pavel On 1/10/14, 1:37 PM, Subhani Bandara wrote:

Dear all,

I have a protein crystallized with metal chelate complexes and some of the atoms of chelators and the metals sit on the two fold axis. Is there a way that I can refine the coordinates of those atoms only along the two fold axis (let's say X) while restraining the coordinate refinement along other two axes (Y and Z)?

Thanks Subhani