[phenixbb] is derivative data useful for looking for the missing part of the model?

[fn1 at rice.edu]

Hi everyone,

I got a partial model, consisting of 80% of the whole molecule, from  
the molecular replacement. The native data reflects to 2.3 A, and now  
the R/Rfree= 0.22/0.28. My problem is that the missing part of the  
model is important for us, but there is not any density for this  
region now.

Meantime, we have several heavy atom derivative data. My question is  
that if refine the model against the derivative data, will the heavy  
atom appear in the difference map if existing? Any suggestions on how  
to use the derivative data to locate the missing part of model?

Thanks in advance!
Regards,
Fengyun