For the SeMet dataset, which wavelength did you collect first? If it is the
peak, you could try doing SAD with just the peak wavelength. Maybe combine the
Se peak data with the Hg dataset (provided they are isomorphous) and do MIRAS
as Jacob suggested.
Bert van den Berg
University of Massachusetts Medical School
Program in Molecular Medicine
Biotech II, 373 Plantation Street, Suite 115
Worcester MA 01605
Phone: 508 856 1201 (office); 508 856 1211 (lab)
e-mail: [EMAIL PROTECTED]
http://www.umassmed.edu/pmm/faculty/vandenberg.cfm
________________________________
From: CCP4 bulletin board on behalf of Jacob Keller
Sent: Thu 7/17/2008 11:23 AM
To: CCP4BB@JISCMAIL.AC.UK
Subject: <spam> Re: [ccp4bb] Advice for phasing
Wouldn't it make sense to do MIRAS with both the Se and Hg derivatives, and add
in some multi-crystal averaging from the native set? You seem like you are
almost there, though. I assume you have already tried DM and NCS averaging (if
there is any)?
Jacob
*******************************************
Jacob Pearson Keller
Northwestern University
Medical Scientist Training Program
Dallos Laboratory
F. Searle 1-240
2240 Campus Drive
Evanston IL 60208
lab: 847.491.2438
cel: 773.608.9185
email: [EMAIL PROTECTED]
*******************************************
----- Original Message -----
From: Junyu Xiao <mailto:[EMAIL PROTECTED]>
To: CCP4BB@JISCMAIL.AC.UK
Sent: Thursday, July 17, 2008 10:13 AM
Subject: [ccp4bb] Advice for phasing
Hi,
I have a very good native data set. However, the selenomethionyl
crystal has a different space group and always suffers from radiation damage. A
three-wavelength data set was still collected, and after phasing in SHARP, some
features can be seen but the map is not good enough for tracing. Then I did
some heavy atom soaking with the native crystals and collected data at home,
however, the crystal was again converted into the same space group as the
selenomethionyl crystal. At lease 4 Hg sites can be found both by isomorphous
difference Fourier calculated using the partial Se-MAD phase and by isomorphous
difference Patterson, suggesting they should be real. Now with these
information, what's the best way to do the phasing in SHARP, or in some other
programs?
I hope I have made myself clear; and I would like to supply more
details. Any suggestion will be highly appreciated.
Best regards,
Junyu
==============================
Junyu Xiao
Department of Biological Chemistry,
University of Michigan
Lab address:
3163 Life Sciences Institute
University of Michigan
210 Washtenaw Avenue
Ann Arbor, MI, 48109-2216
Phone: 734-615-2078
==============================
