Most of the labs sharing our Phoenix have had enough trouble with exactly this that our standard procedure is to now to use 1 µl drops (.5/.5 protein/well) in our initial screens – those scale up much more reliably to the 24-well format and seem less finicky in general, reducing the chances of an unusable hit.  We often get a somewhat different set of hits than we get at the lower volume, as well, so it might be worth rescreening while you work on the existing hit. 

Of course we also try the usual tricks with optimizing anyway (my first crystallized protein precipitated in sitting drops but not hanging drops, etc). J

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Dr. Brian C. Richardson

Weill Institute for Cell and Molecular Biology

Cornell University

(609)933-4548

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Dear All,

I have searched the archives and would like more information about reproducing robot tray hits using 24-well hand trays. I reproducibly get crystals when I use small volumes (0.5 ul) in 3-well intelliplates but only precipitate in 1-2 ul sitting drops in 24-well hand plates.

What parameters should I vary to reproduce crystals in hand plates? References that discuss this procedure exhaustively would also be appreciated.

Thanks,
Matt