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INSIGHTS INTO THE
MOLECULAR MECHANISMS OF PROTEIN FOLDING AND MISFOLDING.
Sheena E. Radford,
University of Leeds, Leeds, UK, LS2 9JT.
Email s.e.radford@leeds.ac.uk; FAX + (113) 233 3167
Recent innovations in protein engineering, protein expression and
methods for monitoring protein folding in real time, have now
placed
scientists at the exciting point of being able to make real
progress
towards understanding protein folding. For a complete
understanding of
folding, we also need not only to consider the problem of protein
folding
in vitro, but also how this process occurs in vivo. This is an
exciting
field involving topical areas such as chaperone-assisted folding
and
protein misfolding diseases. We are investigating all of these
aspects of
protein folding in my research group, using a wide variety of
biochemical
and biophysical methods and a variety of different proteins with
a range of
topologies. In this lecture I will describe recent insights into
the
folding mechanisms of some of these proteins. I will also
highlight some
of the recent results we have obtained which suggest that the
molecular
chaperone GroEL can bind substrates ranging from unstable early
intermediates, to protein conformations resembling closely the
ultimate
native-state. Another important, and currently, very topical
aspect of
protein folding, focuses on the misfolding of proteins in amyloid
diseases.
We are using our knowledge of protein folding mechanisms in
vitro,
gathered using a wide range of biochemical and biophysical
methods, to
investigate the mechanism of amyloidosis of human lysozyme. Our
results
suggest that the amyloidogenic variants of lysozyme are
destabilised
relative to the wild-type protein, but more significantly, they
have
unusual conformational dynamics that might explain their
propensity to
aggregate. We have investigated this further using peptides from
lysozyme
which are thought to be important in fibrillogenesis. We have
shown that
the small peptides also form fibrils, reminiscent, but much more
simple in
structure, than amyloid fibres. This has opened the door to a
detailed
investigation of the mechanism of protein fibrillogenesis, the
results of
which will be described.
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