Hi Lindsey, Obviously, one would need a lot more information to properly diagnose the problem and I am sure much smarter people them me will ask you for that. But just to move the task by couple of steps, I want to point out couple of things. 1. Trivial question: did you have the anomalous option turned on during data processing? (Just like from the IT help - is your computer turned on?) 2. How much data did you collect for each half of the inverse beam geometry? If you have enough, try phasing with only one half. When done properly, inverse beam experiment is great but it can easily get tricky introducing systematic errors and thus swamping anomalous signal. If you redo the inverse beam, use little wider wedges, say, 5-10 degrees. 3. I thought an example of diffraction image would not give any useful information but... Judging by how smooth the background is on your Pilatus image, I am guessing you have used a lot of exposure. Can you calculate how much dose did you put in your crystal? If you are going to re-do the experiment, I would suggest reducing the exposure level and collecting more data. 4. Because you are not showing f' and f" plots, I am guessing that you are doing SAD. If it fails and you end up redoing your experiment and you have crystals for it, you might want to try 2-wavelength MAD but for that you would need to know exactly where is inflection point and collect one of the datasets there.
Good luck! Nukri On Mon, Aug 26, 2019 at 5:45 PM L. Doyle <ldo...@fhcrc.org> wrote: > I have some Seleno-Methionine protein crystals (12 SeMet of 211 amino > acids, incorporation verified by Mass Spec). I've already collected several > datasets (ALS BL5.0.2) but I seem to be losing (rejecting?) a lot of > anomalous signal during data processing. I'm most familiar with HKL2000, > but I have tried XDS and DIALS auto-processing. Here is a scan: > https://ibb.co/LZqm33p and here is an example of a frame: > https://ibb.co/gR3ZR47. Each frame is 0.25° and I'm using inverse beam > with wedge size 1°. Maybe I need to adjust my collection strategy? All > previous datasets have been in space group P 21 with dimensions of approx. > 24.5Å, 85Å, 40Å, 90°, 96.5°, 90°. I'm sure there are additional things I > can be doing in HKL but I've run out of ideas. Any advice or > recommendations would be appreciated. Please let me know if you need > additional information. > > Thank you, > Lindsey > > ######################################################################## > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1 > ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
