Yes, on both counts. SeMet proteins can be frustratingly* close to their native forms - with little quirks like twinning or lack of useful diffraction etc. It's common practice to micro (or macro) seed with native crystals and it often works quite well. It's fun and sometimes useful to add a few ul of micro-seed suspension to the *reservoir* of the crystallization experiment (this conveniently dilutes the stock), mix well, and then set up drops the usual way. If you're not too much off in your initial seed count, this way every condition has (potentially) been seeded - of course in some cases seeds don't survive the conditions in the well, but it is generally safer than adding seeds to protein prior to set up since they are likely to dissolve in the absence of precipitants/buffers/etc.
Artem * is it even a word? who cares... On Wed, Sep 1, 2010 at 10:37 PM, amit sharma <3112a...@gmail.com> wrote: > Dear All, > My SeMet protein crystals have a needle-like morphology, worse than that of > the native xtals. Also, although the cell dimensions of both forms is very > much similar, the SeMet xtals are twinned(as indicated by Ctruncate plots). > I was wondering if such cases were commonly seen, also is it alright to > microseed my SeMet protein drops with seeds from the native xtal. I would be > grateful if someone could shed light on this. > > thanks in advance, > -- > Amit Sharma, > Postdoctoral Fellow, > Department of Biophysics, > Johns Hopkins University, > Baltimore, > MD21218 >
