Ultracold storage

[Rick Neubig]

We just got a new freezer that can go to -86 C and I wondered
if anybody had personal experience with storage of G proteins
and/or 7tm receptors/membranes at different temperatures. We've
always stored them at -70. Do they remain more stable at lower
temps (e.g. -80 or -86).

My initial reaction was "put it as cold as it gets" but apparently
that leads to more problems with frosting up and more stress on
motors and compressors.

So - at what temperature do you all store your precious G proteins
and 7tms_r's and is there any rational basis for the choice?

Rick Neubig
http://www.umich.edu/~rneubig