[sharp-discuss] Extending 3.9A phases to 2.6

[Frank von Delft]

Hi

I'm sitting with a slightly tricky one here, Se-MAD phases to 3.9, 
native to 2.6 (peak,remote,native).  HA refinement runs very stably, 
substructure is complete and all that, now I'm trying to get the phases 
extended to 2.6A, and wanted to ask if there tips for the best solvent 
flattening.

1) Solvent content by matthews should be 76% (enough Se for 1 mol/ASU), 
but I(4) looks better at 50%, as does I(4)/I(1) (which is what solvent 
optimization uses).  Is this usual?

2) I don't see too much difference between the two hands, both for I(4) 
and I4/I1;  does this mean I have not in fact solved the substructure, 
or just that the phase extension is struggling?

3) The envelope looks a bit cleaner for P4132 than P4332, but I don't 
really see protein-like features (the odd sheet or helix would be nice). 

What are the main parameters to play with?  I do a DM run first every 
time, because the sharp maps don't show much info either.

Any tips would be very useful; I scoured the manual but maybe missed the 
useful bits.

Cheers
phx