Hi Manoj, it depends on crystal and hardware (detector, beam, goniometer) quality as well as on the correct strategy whether you will be able to solve the structure with sulfur SAD. 6 sulfur in 12 kDa should be doable, if the crystals diffract to 2.5A or better. Others have given good advice or links on these topics.
My only addition is: you should not assume that there is no radiation damage on the home source, rather, it is very noticeable - see e.g. Sarma and Karplus, "In-house sulfur SAD phasing: a case study of the effects of data quality and resolution cutoffs" Acta Cryst. (2006). D62, 707–716. This means: high-multiplicity data from a single crystal are not guaranteed to be isomorphous. If you have many crystals, however, you could merge several data sets. best wishes, Kay On Tue, 3 Apr 2018 10:26:50 -0400, Manoj Saxena <[email protected]> wrote: >Hi All, > >I am writing to seek advice on doing sulphur SAD data collection >at Cu based home source for a protein that is 12 KDa and has 6 S atoms. >I have seen some links online and some references but would be grateful if >you can share your know-how for success with this. >Like what multiplicity of data would be good to aim for and >data processing tips. >Inputs from people who have tried and failed would also be highly >appreciated. > >Thank you >Manoj Saxena >University of Puerto Rico >
