[phenixbb] is derivative data useful for looking for the missing part of the model?

[Nathaniel Echols]

2010/6/15 <fn1 at rice.edu>

> Thanks so much!It looks promising.
> If I have two or more derivative data and want to combine all these
> information. Can I just do MRSAD individually for each dataset, and combine
> them?
>

Short answer: much of this is already automated in AutoSol, and the model
phases can be used for methods other than SAD.  You'd still run AutoMR to
get the model phases, then run AutoSol with all derivatives at once plus
model phases.  I'm not sure whether it's better to do it as an MIR(AS)
experiment, with your native data and the derivatives, or multiple SAD
experiments (without native data).  Both should be (mostly) straightforward
to set up.

However, the quality of the final phases still depends on the quality of the
derivative data.  If you already have decent phases it is often very easy to
find heavy atoms by eye in the anomalous (or isomorphous, I guess)
difference maps, but this doesn't always mean that you can calculate good
phases using those sites.  It might be a good idea to try running Xtriage on
each of the derivative datasets first to assess the anomalous signal.

-Nat
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