Re: [phenixbb] Difficult dataset and refinement--P422? I422?Twinning?

I agree. The fact that two "crystals forms" appear, with related unit cells: P422 data: unit_cell = 191.6999969 191.6999969 311.0539856 90 90 90 space_group = "P 4 2 2" I422 data: unit_cell = 191.783 191.783 103.775 90 90 90 space_group = "I 4 2 2" indicated to me you have mis-indexed the P422 data. It is likely I422. Kelly ******************************************************* Kelly Daughtry, Ph.D. Post-Doctoral Fellow, Raetz Lab Biochemistry Department Duke University Alex H. Sands, Jr. Building 303 Research Drive RM 250 Durham, NC 27710 P: 919-684-5178 ******************************************************* On Mon, May 7, 2012 at 12:18 PM, Nathaniel Echols wrote:

On Mon, May 7, 2012 at 8:46 AM, Kelly Daughtry wrote:

...

Looking at the P422 data, it look like you have pseudo translational symmetry. Did you try processing this data as I422?

From the P422_xtriage.log:

The full list of Patterson peaks is:

  x      y      z            height   p-value(height) ( 0.500, 0.500, 0.165 ) :   78.635   (6.634e-07) ( 0.000, 0.000, 0.330 ) :   56.292   (2.795e-05) ( 0.500, 0.500, 0.497 ) :   30.920   (1.207e-03)

One word of caution: an exceptionally high off-origin peak can mean that the unit cell was measured too large, and you've integrated extra reflections that are really non-existent.  (I'm not sure what the threshold for this is, but 80% seems pretty large.)  Splitting and various indexing artifacts can sometimes lead to this.  I'd recommend running labelit.index on the images and seeing what it thinks the lattice should be.

-Nat _______________________________________________ phenixbb mailing list [email protected] http://phenix-online.org/mailman/listinfo/phenixbb