Dear Yujie,

You have salt crystals in your loop, as evidenced by some very strong reflections at high resolution. On the left, at nine o’clock, again at high resolution, you have a collection of spots that do not seem to fit to a single lattice. Since the low resolution region looks much cleaner, this might again be salt or some other small molecule that formed multiple micro crystals.

However, the diffraction at low resolution looks like a bona fide macromolecular crystal (protein and/or RNA). What I would do is to apply a resolution cut-off and only use the low resolution data for indexing. Once you found a good indexing, you could process the data including the high resolution data as well.

Good luck!

Herman

Von: CCP4 bulletin board [mailto:[log in to unmask]] Im Auftrag von Liu Rachel
Gesendet: Mittwoch, 12. Oktober 2016 08:55
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Betreff: [ccp4bb] strange X-ray diffraction diagram——RNA Or Complex？

Dear everyone:

Recently, I suffered a problem during my research work. I purified a zinc finger protein, and crystallized as a beautiful cube in a reservoir solution only containing phosphate as the precipitant, no other buffer or molecules. However, regardless of multiple optimization, the crystal diffracted badly (7~8 Å best). I have also tried co-crystallization with dsRNA because this protein can  bind to dsRNA. Then crystals grow in a new condition（2.5M (NH₄)₂SO_4，0.1M BTP,  pH7.0）and its form change to cluster of needle. But the X-ray diffraction diagram is very strange（as shown in the picture）. The Data cannot be processed with HKL2000 either. I want to figure out, could this be a RNA crystal rather than the complex?   Or is there anybody know about the crystal of RNA molecular？

Thank you very much!

Yujie Liu 
Room 2071, research center in life sciences,
China Agricultural University 
No. 2 yuanmingyuan west road, Haidian District, Beijing, 100193  P.R. China 
Tel: (86)-10-62734078