On Tue, Jun 15, 2010 at 4:03 PM, Francis E Reyes

wrote:

Using the model to find the heavy atom sites and then calculating phases on those sites (without model) might help. ( I believe phenix will output a phase combined map (model + experimental phases)).

Correct, this is the default behavior if you provide a model directly to AutoSol (or Phaser). There is however a semi-automatic way to use the model phases to find sites without biasing the experimental map; see the documentation here: https://www.phenix-online.org/version_docs/1.6.2-432/autosol.htm#anch126 (The AutoBuild step is optional - you could just look at the density-modified map after AutoSol is done.) -Nat

2010/6/15

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