Canada Research Chair Renewed


Peter Loewen, Microbiology, Canada Research Chair in Protein Chemistry

posted 9 April 2010

Dr. Loewen's web site

Minister of State for Democratic Reform Steven Fletcher announced the renewal of four research chairs at the University of Manitoba, including that of Peter Loewen, Microbiology. Chairholders are research leaders or rising stars in natural sciences and engineering, health sciences, or social sciences and humanities. The University of Manitoba has 49 Canada Research Chairs: eight in the Faculty of Science.

"This government is investing in research, science and technology to improve Canadians' quality of life, create jobs and strengthen the economy," said Minister Fletcher. "The Canada Research Chairs program is helping our universities develop, attract and retain talented people, strengthening our capacity for leading-edge research, while building economic opportunities and the jobs of the future for Canadians."

Loewen's research focuses on the structure and function of the proteins which play a key role in the promotion of health and the combating of disease. His work involves the characterization of cellular responses to oxidative stress, which occurs when reactive oxygen - commonly called 'free radicals' in health food stores - accumulates faster than it can be removed by our bodies. Loewen is also interested in the mechanisms by which a certain group of enzymes destroy hydrogen peroxide before it breaks down and damages cellular components.

The video clip (Windows Media Play 10 or hirer is needed to play the clip) that Loewen created illustrates the complexity and inherent beauty of proteins at the atomic level.  Loewen is studying the enzyme that activates the anti-tubercular drug, isoniazid.  Enzymes are proteins that catalyze reactions in all organisms. This enzyme is composed of two identical protein subunits (red and blue in the model) and each protein has a heme (as in blood hemoglobin) group at the active center in yellow where reactions take place.

A single protein molecule or subunit in blue is shown as a ribbon to illustrate the intricate folding inherent in a protein.  The overlapping green protein illustrates how another related protein shares a similar folded architecture in a much smaller protein. The second subunit (blue), when it appears, provides an impression of the overall complexity of the very large protein complex.

The ribbon diagram morphs into a surface covering to provide an idea of the uneven nature of the surface of a protein.  The significance of the many crevasses and channels leading into the protein is that this is where small molecules bind to the protein and reactions occur. To illustrate this the heme active site is approached through a channel which is the path that would be followed by a substrate.