Dear Nazia Nasir, it is important to know what you do BETWEEN the refinement cycles. Rfree not moving and R1 dropping is often a sign of overfitting, i.e. you might be adding water molecules into the noise or refine the occupancy of single atoms, e.g. in a ligand or of the water molecules.
As a general rule, carry out as much model building as possible and run as few refinement runs (not cycles within a run!!!) as possible. Best, Tim On 12/10/2013 07:51 AM, Nazia Nasir Phd2009,ProteinCrystall.Lab wrote: > Hi, > > I am facing a problem in refining one of my structures. With every > refinement the Rwork is going down. However, the Rfree is stuck and is > not going down with refinement. I have already solved the structure > without the co-factor bound. This structure is with the co-factor > bound. Can anyone suggest the reason for the Rfree getting stuck? > > Thanks > -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A
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