Our laboratory is focusing on the study of
protein folding and molecular recognition and we are
particularly interested in the role these processes may
play in the pathophysiology of Alzheimer's disease.
We are using bovine pancreatic trypsin
inhibitor (BPTI) as a model system for the protein
folding studies. BPTI is a small, globular, 58 amino acid
polypeptide and our approach has been to express a
recombinant gene for this inhibitor in E. coli and
produce, via site-directed mutagenesis, mutants of BPTI
having perturbed folding. The folding of these mutants is
then characterized in vitro in terms of the
thermodynamics and kinetics of the process.
Our work on molecular recognition has
centered on the well-characterized protease-protease
inhibitor interaction. The specific model system we have
employed is the interaction of avian ovomucoid third
domains (OM3D) with members of the trypsin family of
serine proteases. Our approach is similar to that
described above with BPTI, namely the expression of
recombinant OM3D in E. coli and specific mutagenesis of
reactive site residues. Mutant inhibitors are then tested
for binding affinity with a panel of serine proteases.
Investigations of the physiological roles that such
inhibitors play in vivo are also ongoing.
The Alzheimer's b amyloid precursor protein
(APP) is a large, membrane-bound glycoprotein that is
expressed in the body from several different
alternatively-spliced mRNAs. Contained within this
precursor is the amyloid ß peptide which has been
strongly implicated as a causal agent in Alzheimer's
disease. Our laboratory is currently using a protein
engineering strategy to dissect the structure and
function of the APP molecule as well as its component
domains. We are also seeking to identify and isolate
other proteins in the body that bind to APP. By
characterizing these features of APP biology we hope to
illuminate its role in both normal and diseased
tissue.
