Hi Alex, Your anomalous signal seems to extend to about 4 A. Xtriage will also report a resolution limit for your useful anomalous data. What do you mean by "merged"? Merging multiple observations of the same hkl or averaging Friedel mates? You should use a merged file (observations) for Xtriage (as suggested by Peter Zwart), but if you want to have some statistics of the anomalous signal, you have to use a file where Friedel mates are kept separate. So why don't you use your file from aimless for xtriage? As you posted above, aimless found anomalous signal, so the output should keep the data separate. BTW, maybe you can extend the resolution of your data set, I/sigma is 2.9 in the highest shell. Or are you limited by detector geometry? And as Ryan said, just try phasing/heavy atom search. No anomalous signal indicator can tell you beforehand if phasing will be successful. Best wishes, Dorothee On Tue, Apr 12, 2016 at 1:59 PM, Alex Lee wrote:

Hi Dorothee and Billy,

Thank you for your information! I have both I, SIGI and IPR, SIGIPR labels in my unmerged MTZ (I checked this with ViewHKL). But it seems the Xtriage only offers choices to merged mtz. I tried to choose I,SIGI, Merged option (even though my mtz is unmerged), the Xtriage output shows "anomalous flag false" and I did not get any additional anomalous information from the report.

On Tue, Apr 12, 2016 at 12:16 PM, Dorothee Liebschner < [email protected]> wrote:

...

Hi Alex,

What data labels are in the file pointless_xxx.mtz? You can check with

...

phenix.mtz.dump pointless_xxx.mtz The output should list the available labels. (you should see the labels also in hklview)

You cannot leave the data labels choice blank in xtriage, as you have two data choices in your file, so you need to tell the program which ones to use.

Apart from xtriage, it is always helpful to check the anomalous signal reported in various log files from your data processing steps, such as aimless.log and also from mosflm (I am not familiar to mosflm but I guess it outputs also some info about anomalous signal?).

Best wishes,

Dorothee

On Tue, Apr 12, 2016 at 11:08 AM, Alex Lee wrote:

...

Dear Phenixbb members,

I have a data-set of a 8 kDa protein crystal around 2.5A resolution. The protein crystal was soaked in potassium iodine before collecting data using in-house beam (1.54A wavelength). As I expected some anomalous signal from the iodine ion from the crystal, after I use Imosflm to index, integrate and scale the data (space group P3). I got four output .mtz files: pointless_XXX.mtz; aimless_xxx.mtz; ctruncate_xxx.mtz; ctruncate_xxx-unique.mtz. After I check with viewHKL, I found the only unmerged mtz data is pointless_XXX.mtz, the other three mtz files are merged.

The next step I tried to use Phenix Xtriage (Linux version 1.10.1) to check my mtz data for anomalous completeness, I thought in this step my mtz should be unmerged type to see the anomalous signal, so I chose "pointless_xxx.mtz" as Xtriage input, but for the data labels in the Xtriage GUI panel, I can only have two choices of "I, SIGI, Merged" and "IPR, SIGIPR, Merged", it seems I do not have a choice of an unmerged mtz label. I decide to leave this choice blank by choosing data labels"---". After I click "run", Xtriage gave an error "please select labels for input data".

Any input on this issue?

Thanks in advance.

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