Avanti-Biophysical
Society Award 2001 Winner
Ronald McElhaney, Ph.D.
Professor of Biochemistry
The University of Alberta
Edmonton, Alberta
Canada
Research Interests
We are interested generally in the structure and function
of biological membranes and particularly in the roles that the various
membrane lipids play in these complex supramolecular structures. In
our own laboratory we currently utilize four physical techniques (X-ray
diffraction, differential scanning calorimetry, Fourier transform infrared
spectroscopy and nuclear magnetic resonance spectroscopy) to study lipid
thermotropic phase behavior and lipid molecular orientation and dynamics
in model and biological membranes. We also actively collaborate with
some half-dozen other laboratories throughout the world who study our
membrane systems with a variety of other physical techniques. We are
particularly interested in the mechanisms by which subtle changes in
the structure of lipid polar head groups and hydrocarbon chains can
profoundly affect their physical properties and their interactions with
cholesterol. We also study lipids that can form non-bilayer structures
under certain conditions and their roles in biological membranes.
We are also interested in both the structural and functional
aspects of lipid-protein interactions. We are currently studying the
interactions of synthetic alpha helical hydrophobic transmembrane peptides
with lipid bilayers. We have found that the structure and topology of
these peptides can effect the properties of the host bilayer in a variety
of lipid-specific ways, and that the physical properties of the lipid
bilayer can in turn effect the conformation and disposition of the peptide.
We are also studying the interactions of the antimicrobial peptide gramicidin
S and it's analogs with lipid model and biological membranes, as part
of a PENCE project on protein design. We have
gained important insights into the binding and mode of permeabilization
of the lipid bilayer by these peptides and have shown that their lipid
specificity can be used to improve their antimicrobial potency while
minimizing their adverse effects on animal cell membranes.
Finally we are also investigating the relationship of
lipid fluidity and phase state and cell growth, passive permeability
and several membrane-associated enzyme and transport systems, in both
model and biological membranes. In these studies we often utilize the
plasma membranes of Acholeplasma laidlawii B, a simple, cell wall-less
procaryotic microorganism whose membrane lipid fatty acid composition
and cholesterol content can be altered in a dramatic yet systematic
fashion. A (Na++ Mg++) - ATPase from the plasma membrane of this organism
has been isolated and used in an extensive series of lipid-reconstitution
studies. In all of our studies we strive for both physical and chemical
rigor and biological sophistication and relevance.
For more information on Dr. McElhaney's research, also
see his listing in the Community
of Science database.
Selected Publications
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