[ccp4bb]: Vibration (was re:Dehydration)

[Richard Gillilan <reg8@cornell.edu>]

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Hemant Yennawar wrote:

> Hello Ccp4bb,
> One of the magic bullets (as we all know, each protein needs a different
> one) for improving
> crystal quality was floatation of the crystallization trays.  Floating the
> trays isolate
> them from the vibrations.  We used a sheet of styrofoam  as a floating
> platform for the tray.
> Further, to avoid evaporation of the water under the styrofoam sheet,  a
> dessicator with lid was used.  Hope some other proteins also yield to this
> treatment.
>

Recently, I set out two identical trays of lysozyme (hanging drops).
One I put on the usual shelf, the other I put on top of our 6-processor
Linux cluster. Both trays were put inside styrofoam coolers at room
temperature with thermometers ... there were no significant temperature
differences between the two.

After 3 days, the tray on the shelf yielded the usual lovely crystals.
Much to my surprise, the tray on the Linux cluster had almost NO
crystals at all ... even after more than a week.  After a couple weeks,
I removed it to a regular shelf and crystals formed over night.

Conventional wisdom, would be that vibration increases nucleation ....
but this would seem to demonstrate the opposite.  The cluster really does not

vibrate much ... it is barely perceptable to the touch
..... so .... It may not be a good idea to have a computer on the same
bench as your crystal trays.

Floatation sounds like a great idea. I had recently borrowed a motion
isolation table that uses gas floatation, but have not yet started using it.

Has anyone else done systematic vibration experiments?
I only have a couple literature references.


Richard Gillilan
MacCHESS
Cornell University