Dear Elisabetta,
from the statistics you attach it seems that your low resolution extends only to 6.72 A
My guess is that if you could include as much low resolution as possible (e.g. up to 20A or more)it will help a lot in getting better maps etc.,
I hope this is the answer you are looking for!!
please let me know what happens next!
ciao ciao
Stefano
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Stefano Benini PhD
Structural Biology - DECS
Mereside 50S38
Alderley Park
Phone:+44-1625-518293 (ext.: 28293)
http://structuralbiology-ap.rd.astrazeneca.net/people/Stefano-Benini/Stefano-Benini.html
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-----Original Message-----
From: CCP4 bulletin board [mailto:[log in to unmask]]On Behalf Of
Sabini, Elisabetta
Sent: 15 August 2007 18:35
To: [log in to unmask]
Subject: [ccp4bb] "Dry" structures
Dear all,
what does it mean when a structure doesn't have many water molecules?
I have a 2.3A data set, 2 molecules in the AU (260 residues each), space
group C2221 - I haven't finished my water search but I don't seem to have
more than 20-30 obvious/good water molecules. The Rfac/Rfree are 22/30%,
the protein is modeled and the ligands are in.
I collected the data at APS SERCAT ID-22. Did I have a dry crystal (!!) or
did the beamline dried it up?!
How many water molecules should I expect at this resolution?
Also, what does it mean when a strong peak in the Fobs-Fc doesn't have the
corresponding 2Fobs-Fc map covering it even at very low sigma?
Thank you!
Eli :o)
PS: I have attached the statistics for the data set from XDS
--
Elisabetta Sabini, Ph.D.
Research Assistant Professor
University of Illinois at Chicago
Department of Biochemistry and Molecular Genetics
Molecular Biology Research Building, Rm. 1108
900 South Ashland Avenue
Chicago, IL 60607
U.S.A.
Tel: (312) 996-6299
Fax: (312) 355-4535
E-mail: [log in to unmask]
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