Dear benevolent experts,

I am trying to use Phaser for molecular replacement with EM-map as a model.
The EM map, originally in a small P1 cell, was put in large P1 using CCP4's MAPROT and a mask that was defined by a certain cut-off level.
Could you please advise me how to derive the EXTEnt and CENTre parameters needed for ENSEmble building ?
Does the simple way of giving the size of the original P1 as the EXTEnt and its centre as CENTre sound reasonable ?

I would be grateful for any advice and comments,

Peter.