[phenixbb] Same enzyme, different space groups ?

[Patrick Loll]

For spacegroup 96, the Int'l tables show the following reflection conditions:

0 0 l: l = 4n
h 0 0: h = 2n

So your assertion of zero systematic absences is incorrect.

When in doubt process in the lowest symmetry point group (which I guess would be 422 here), and look individually at I and sig(I) for the relevant reflxns


On 28 Mar 2011, at 6:23 PM, Yuri wrote:

> Hello everyone,
> I was comparing 2 data sets I have and when I run Xtriage I noticed the following:
> a) for one crystal (data processed in P 4 2 2)
> 
> | space group | n absent | <Z>_absent | <Z/sigZ>_absent | +++ | ---  | score       |
> ------------------------------------------------------------------------------------
> | P 41 21 2   | 24       |     0.03   |     1.30        |  0  |  2   | 0.000e+00  |
> | P 43 21 2   | 24       |     0.03   |     1.30        |  0  |  2   | 0.000e+00  |
> | P 42 21 2   | 22       |     0.03   |     1.27        |  0  |  4   | 7.187e-02  |
> | P 4 21 2    | 18       |     0.01   |     1.21        |  0  |  8   | 3.035e-01  |
> | P 41 2 2    | 6        |     0.11   |     1.59        |  0  |  20  | 9.065e-01  |
> | P 43 2 2    | 6        |     0.11   |     1.59        |  0  |  20  | 9.065e-01  |
> | P 42 2 2    | 4        |     0.13   |     1.57        |  0  |  22  | 9.784e-01  |
> | P 4 2 2     | 0        |     0.00   |     0.00        |  0  |  26  | 1.210e+00  |
> ------------------------------------------------------------------------------------
> 
> b) the other crystal, of the same enzyme (data scaled in P 43 21 2) x triage tells me this crystal is in P 43 21 2.
> 
> | space group | n absent | <Z>_absent | <Z/sigZ>_absent | +++ | --- | score       |
> -----------------------------------------------------------------------------------
> | P 4 2 2     | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 4 21 2    | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 41 2 2    | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 41 21 2   | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 42 2 2    | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 42 21 2   | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 43 2 2    | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> | P 43 21 2   | 0        |     0.00   |     0.00        |  0  |  2  |  0.000e+00  |
> -----------------------------------------------------------------------------------
> 
> My understanding is that P 43 21 2 should have 0 systematic absences (if I am wrong, please point it out)
> 
> My questions are:
> what is really my space group? Or should I say space groups, if indeed I have two different space groups.
> How do I nterpret the scores?
> Could it all be a function of the space group they were processed in?
> 
> 
> 
> --
> Yuri Pompeu
> 
> _______________________________________________
> phenixbb mailing list
> phenixbb at phenix-online.org
> http://phenix-online.org/mailman/listinfo/phenixbb