[phenixbb] Pseudotranslation issue

[Fulvio Saccoccia]

Dear phenixbb,
     I have a data set collected at 2.2A resolution that I can integrate 
in P4. Aimless, Phaser and Xtriage recognized a pseudotranslation  
(34.6% of origin peak) at fractional coordinates 0.500 0.500 0.479  
(ORTH   46.7   46.7   37.4). However labelit.index run with 
sublattice_allow=true search did not detect the pseudotranslation 
vector. So far, any attempts to phase by molecular replacement was 
unsuccesfull and I suspect that it could be due to incorrect assignement 
of space group:

Now, some questions arise:
1) does the pseudo translation exist or do not?
2) if translational NCS is present, could it mimic a P41/P42/P43 space 
group?
3) in any case, any advices in order to properly deal with tNCS will be 
of great help?

I thank you in advance
Best wishes

-- 
Fulvio Saccoccia, PhD
Sapienza University of Rome
Dept. of Biochemical Sciences "A. Rossi Fanelli"
Piazzale Aldo Moro, 5
00185 Rome (Italy)