It would help if we knew the crystallization conditions and the protein 
solution components. Also, what are the map sigmas and e/A^3? It seems odd that 
there isnt positive density on the Fo-Fc map across the entire blob seen on the 
2Fo-Fc map, considering you do not have anything modeled in. My guess is that 
your Fo-Fc map is at a much lower e/A^3 compared to your 2Fo-Fc map and what 
you are seeing is basically just greatly amplified noise. Try placing 3 waters 
in the blobs you see on the 2Fo-Fc map and see if that helps. 

------------------------------------------------------------------------------- 
Greg Costakes 
PhD Candidate 
Department of Structural Biology 
Purdue University 
Hockmeyer Hall, Room 320 
240 S. Martin Jischke Drive, West Lafayette, IN 47907 

--------------------------------------------------------------------------------
 
** Hard work often pays of in time, but Procrastination always pays off now ** 

----- Original Message -----
From: "stacy William" <stacy.biot...@gmail.com> 
To: CCP4BB@JISCMAIL.AC.UK 
Sent: Thursday, January 19, 2012 1:44:30 AM 
Subject: [ccp4bb] extra density ?? 

Dear All, 
I am working on plant proteins and solved a structure, there is an extra 
density which i cannot fix . I am attaching the coot image , can anybody 
suggest me what it could be 


THANKS :) 

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