Hi Oliver,

it is only used to calculate correlation between experimental map and map calculated form the model (model-map CC). When you run phenix.real_space_refine you provide model and experimental map as inputs. To calculate model-map CC you need to calculate map from atomic model first. This is done by first calculating structure factors Fcalc from the model up to specified resolution and then FT'ing them into Fourier map that is then used to calculate CC.

Pavel

On 8/16/16 09:59, Oliver Clarke wrote:

Hi,

What exactly does phenix.real_space_refine do with the mandatory "resolution=" keyword when refining a model against a ccp4/mrc formatted map?

Is this purely for adjusting restraints etc, or does phenix internally low-pass filter or resample the map based on this parameter?

This seems like a basic question, so I apologize if the answer is staring me in the face, but I couldn't see it in the online documentation or in the output of phenix.real_space_refine --help.

Cheers
Oliver.