Hello community, I wonder if I could solicit advice about a problematic
dataset. I plan to solve the structure by molecular replacement and expect
that the protein is relatively compact, ie not elongated. SAXS data
supports this expectation.
The crystals diffract to 2.6 Å resolution and appear to be in P 21 21 2
with a = 49, b = 67, c = 94, which should fit <=2 molecules in the ASU with
40% solvent. The native Patterson shows a large peak (12 sigma) suggesting
a tNCS vector of {0.5, 0.5, 0}.
If you're sharper than me, you may have already spotted the problem - c is
the long axis of the unit cell, but tNCS constrains the proteins to a plane
parallel to the a,b plane. Indeed, molecular replacement attempts using
Phaser will not give a solution in any orthorhombic space group unless I
turn off packing, and then I get large overlaps in the a,b plane and huge
gaps along c.
Since I believe that my model is good (or at least the correct shape, based
on SAXS), I wonder if I'm misinterpreting my crystallographic data. Any
insights into how to approach this problem would be much appreciated.
--
Kevin Jude, PhD
Structural Biology Research Specialist, Garcia Lab
Howard Hughes Medical Institute
Stanford University School of Medicine
Beckman B177, 279 Campus Drive, Stanford CA 94305
Phone: (650) 723-6431
########################################################################
To unsubscribe from the CCP4BB list, click the following link:
https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
