Hi,<br><br>I am trying to solve a protein-RNA complex structure - space group is either P4(1)22 or P4(3)22. Even though data seems to have enough Se-anomalous signal, we are unable to get any solution. I have tried even lower symmetry such as P4(1), P4(3), P4, P222(1), C222(1), and P2(1). <br>
Now I am worried if my data is twinned. Cumulative intensity distribution (using scalepack2mtz) looks normal in all the space groups. Data analysis using phenix.xtriage indicates presence of perfect twinning or higher symmetry when analyzed in space group P4(1) or P4(3). As I have read, when twin axis is parallel to one of the symmetry axis, data can show artificially higher symmetry and cumulative intensity distribution in such cases shows normal profile. I can work on improving anomalous signal if it is not good enough but before that I want to be sure if data is not twinned. Now how do I make sure that my data is fine and not twinned.<br>
<br>I need your suggestions.<br><br>Thank you <br>Kumar<br>