Dear all

I have a few native datasets, one anomalous dataset with signal up to 10 A and two other datasets (also collected at the phasing wavelength but no anomalous signal seems to be present) and a sulfur SAD dataset with signal to about 7 A. All the datasets have a resolution of about 2-3 A and processed with xia2/XDS.

I couldn't do fluorescence scan as the detector couldn't detect at such a high energy (20 keV).

A few questions:

1. Why is there at least some signal from one dataset but not others? The signal should come from a covalently bound ligand, molybdopterin to be precise.

2. Since I(+) should not be equal to I(-) when there is anomalous signal, should I just merge the native dataset together with those collected at phasing wavelength that have no anomalous signal? Or do I merge everything together?

3. Will the anomalous signal to 10 A be useful to do MR-SAD? I could solve the structure with MR but I wanted to be sure my ligand is there.

Thanks.