One might first look at the predictions, to see what has *actually* been indexed….

My guess it is only the main lattice, with no prejudice against incommensurate modulation

or some other problem. Microscopic twinning analysis does not tell about the

splits of the reflections, that would be macroscopic (multiple domains/lattices), which

might also be possible (needs more analysis).

Best, BR

From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of Jarrod Mousa
Sent: Monday, April 18, 2016 8:18 AM
To: [log in to unmask]
Subject: [ccp4bb] Unusual diffraction

Dear community,

I collected data from a crystal grown in 30% PEG 8000, 200 mM ammonium sulfate, 100 mM sodium cacodylate pH 6.4 and 40% v/v Pentaerythritol ethoxylate (3/4 EO/OH), and cryoprotected with 20% glycerol. I am attaching a snapshot of the diffraction pattern along with a zoomed in portion. I am having trouble solving by molecular replacement, even though I have a very good starting model. Just wanted to get people's insights into the odd (at least to me) diffraction pattern. The data can process with XDS in P 4 2 2. I also attached merging statistics.

Thank you,

Jarrod Mousa

Post-doctoral research fellow

Crowe Laboratory

Vanderbilt University Medical Center