[Protein-analysis] Re: Mechanism Of Cold Denaturation

Dr Engelbert Buxbaum via proteins%40net.bio.net (by engelbert_buxbaum At hotmail.com)
Mon Jan 15 12:06:41 EST 2007

Protenger wrote:

> Hi all
> I'm confused about cold denaturation, I read "cold denaturation of
> proteins" by privalov, but beside
> thermodynamics explanation of this phenomenon there must be molecular
> mechanism by which this type of denaturation can be described.
> I would be appreciated if anybody give simple description of
> thermodynamics concept of this event
> but also molecular mechanism of that.

The bond energies of the various interactions that are responsible for
secondary and tertiary structure are energy dependent, as is the motion
of the atoms that make up proteins. The temperature coefficients however
are different, so that bonds become dominating at one temperature, which
are not dominating at another. As a result in the cold the structure of
lowest free energy may be different from that at 37 degrees. Especially
if you cool slowly, thus allowing the new structure to be achieved
(anealing). Cooling quickly may trap the protein in the higher
temperature structure, since the mobility drops with temperature. That's
why we snap-freeze our samples.

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