[Fwd: [ccp4bb]: re Semet from David Borani]

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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-------- Original Message --------
Subject: [ccp4bb]: re Semet from David Borani
Date: Fri, 11 May 2001 12:04:30 -0700
From: "Bernhard Rupp" <br@llnl.gov>
To: "Ccp4" <ccp4bb@dl.ac.uk>

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I am having trouble posting to the BB;
Bernard, perhaps you could forward this

I don't understand the rather cavalier attitude towards Se-Met
oxidation.
For
one of the proteins I worked on, Apo A-I, oxidation of the (sulfur)
methionines
DRAMATICALLY alters the physicochemical and biological properties of the
protein. The reason is obvious....Met is a hydrophobic side chain;
oxidized
Met
is VERY hydrophilic (it is basically like the universal solvent DMSO)
and
has a
strong, permanent dipole moment.

I would imagine that the properties of most proteins would be altered if
you
suddenly stuck a (delta+)Se--O(delta-) bond in the middle of the
hydrophobic
core. I think care to prevent Se-Met oxidation is called for.

David Borhani
Abbott Bioresearch Center
Worcester MA 01605
508-849-2944
borhand@basf.com