Hi all,

I am trying to solve a structure through experimental phasing using AUTOSOL. I have a couple of heavy atom derivative datasets (Hg, La, Eu, Cd) and also a SeMet data. Unfortunately all the datasets are of low resolution (3.7-4.2A) and there are possibly 4-8 molecules in the asu. MIR, SAD and MAD alone did not give any convincing solution.

However, MIRAS, with a combination of few heavy atom datasets and the anomalous data from SeMet crystals, gave a somewhat satisfactory map. But the heavy atom site picked by AUTOSOL list only one of the heavy atoms i.e. Lanthanum. In another set of run, the solution of which was not convincing, the heavy atom substructure had only Hg. There are 6 Met out of 200 residues in one molecule and mass spec results show that Se incorporation is 100%.

Now, my doubt is that why does the heavy atom substructure contain only La and how can I get the substructure involving Se from this solution (or the datasets used)? Se location is going to help me a lot for finding a starting point to assign side chains.

Any suggestion would be greatly appreciated.

Thanks