Ouch! I completely agree re: single proteins, but I had always found/heard that protein-protein complexes tolerate freezing/thawing less-well that their individual components.
Irrespective of generalisations, In the posted case, where apparently, before freeze complex is intact and concentrated, after freeze complex is less concentrated and degraded, surely the most straight-forward fix is to not freeze it? Dave -- Delivered via an Android. On Apr 22, 2010 8:57 AM, <[email protected]> wrote: Hello- Sorry to be disagreeable, but I think it depends on the protein. We’ve had much better success in getting reproducible crystals when we’ve snap frozen in liquid nitrogen in small aliquots (thin walled PCR tubes work best). We can then screen and optimize using the same protein prep- and again, it is much more reproducible than doing a fresh prep each time. Of course this is only for the few hundred proteins I’ve worked on and it has only been for 98% of the cases examined. Cheers, tom ------------------------------ *From:* CCP4 bulletin board [mailto:[email protected]] *On Behalf Of *David Briggs *Sent:* Thursday, 22 April 2010 5:27 PM *To:* [email protected] *Subject:* Re: [ccp4bb] degradation of protein durring freez thaw Hi, Obvious answer - don't freeze it. If you cannot set your crystallisation screens up straig...
