Hi,
The autoindexing picks this unit cell pretty much unambiguously, and the
profiles look reasonable. These are crystals of a very large heterodimer (2177
residues), and this unit cell would have 2 heterodimers and 56% solvent, which
seems reasonable. Scaling and merging produce reasonable statistics (I used
aimless, not XSCALE):
Overall InnerShell OuterShell
Low resolution limit 19.91 19.91 3.04
High resolution limit 2.99 16.38 2.99
Rmerge (within I+/I-) 0.339 0.040 0.907
Rmerge (all I+ and I-) 0.348 0.045 0.949
Rmeas (within I+/I-) 0.360 0.042 0.994
Rmeas (all I+ & I-) 0.359 0.046 0.997
Rpim (within I+/I-) 0.119 0.014 0.393
Rpim (all I+ & I-) 0.085 0.012 0.291
Rmerge in top intensity bin 0.053 - -
Total number of observations 1981569 5075 44784
Total number unique 112524 338 4559
Mean((I)/sd(I)) 10.6 53.4 2.6
Mn(I) half-set correlation CC(1/2) 0.993 0.999 0.527
Completeness 98.8 43.7 82.1
Multiplicity 17.6 15.0 9.8
Rmerge is high in the outer shell, but looks ok to me across the rest of the
data. The oscillation angle is correct.
The native data set also indexes with the same spacegroup and a slightly
smaller unit cell (a=134 b=148 c=274), I attributed the difference to the Pt
soak.
The only ambiguity is one of the screw axes, so it may be P22121 or P212121.
My XDS.INP has SPOT_RANGE commented out so I believe the default is to use all
the data for indexing.
Cheers,
Jason.
--
Jason Busby
PhD Student
Laboratory of Structural Biology
School of Biological Sciences
University of Auckland
Thomas Building 110
3a Symonds St
Private Bag 92019
Auckland 1142
New Zealand
ph: +64 9 3737599 ext 84155
fx: +64 9 3737414
On 17/07/2012, at 3:02 PM, Bosch, Juergen wrote:
Hi Jason,
if you look at the generated profiles in INTEGRATE.LP do they seem reasonable ?
Does XSCALE.LP produce reasonable I/SigI statistics and expected Rvalues ? If
not this might be another hint at wrong cell/spacegroup perhaps.
You can try collecting spots from your whole data set with SPOT_RANGE= [start
frame] [end frame] and then index the data. If you get too many strong spots
you can select the top 5000 from SPOT.XDS.
Is the oscillation correct in your script ?
Jürgen
P.S. we just collected some data on a 460Å cell
On Jul 16, 2012, at 5:52 PM, Jason Busby wrote:
Hi,
I have a crystal with a large unit cell in P21221 (a=134 b=151 c=276) and I'm
wondering if I have a problem with overlaps. I have a native dataset, and am
trying to get phases. I've collected a Pt soak data set on our home source
with a 0.5˚ oscillation angle, but the anomalous signal drops off after about
8Å. I am wondering if this is a problem due to overlaps at higher resolution.
The Pt dataset has been integrated with XDS, and there don't seem to be too
many rejects, but looking at FRAME.CBF it looks like the predicted spots are
overlapping at higher resolution. You can see a zoomed-in part of FRAME.CBF
here:
http://imgur.com/1WShV
Should I be concerned with this? The crystal mosaicity from XDS is 0.25, so
fairly low. What can I do about this, should I try smaller oscillation angles?
Thanks,
Jason.
--
Jason Busby
PhD Student
Laboratory of Structural Biology
School of Biological Sciences
University of Auckland
Thomas Building 110
3a Symonds St
Private Bag 92019
Auckland 1142
New Zealand
ph: +64 9 3737599 ext 84155
fx: +64 9 3737414
......................
Jürgen Bosch
Johns Hopkins University
Bloomberg School of Public Health
Department of Biochemistry & Molecular Biology
Johns Hopkins Malaria Research Institute
615 North Wolfe Street, W8708
Baltimore, MD 21205
Office: +1-410-614-4742
Lab: +1-410-614-4894
Fax: +1-410-955-2926
http://lupo.jhsph.edu<http://lupo.jhsph.edu/>
