Gerald F. Audette

Gerald F. Audette

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Associate Professor

Department of Chemistry

York University

 

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Research Interests

Current Research

Current research interests include structural investigation of the type IV secretion system (T4SS) and its role in bacterial conjugation, the characterization and functionalization of pilin-dervied protein nanotubes, and the correlation of multiple biophysical techniques to investigate protein structure and function. Please see the Research page for more details.

 

Doctoral Research

My doctoral research was carried out in the laboratory of Dr. Louis Delbaere in the Department of Biochemistry at the University of Saskatchewan. My doctoral research had a dual focus, though both projects were examined using X-ray diffraction methods. The first research focus was the investigation of a lectin-carbohydrate complex. The lectins are a class of proteins which exhibit a high binding specificity towards carbohydrates, yet are non-immunogenic and non-enzymatic. The lectin being studied in this project was the first lectin from Ulex europaeus (UE-I), which exhibits specificity for the O(H) human blood group determinant [alpha-L-Fuc-alpha-(1-2)

-beta-D-Gal-beta-(1,4)-beta-D-GlcNAc].This trisa-ccharide is present on O-type erythrocytes, and is the precursor for both the A and B blood-group determinants. The structure of the native (uncomplexed) UE-I has been published in J. Mol. Biol., and the paper describing the UE-I:carbohdyrate complexes has can be found in a special issue of Can. J. Chem. dedicated to Prof. Raymond Lemieux, a long-time collaborator. The second research focus was the investigation of the regulatory form of the protein HPr from the Gram-positive bacterium Enterococcus faecalis. In Gram-positive bacteria, HPr is phosphorylated at the conserved Ser46 in a regulatory fashion to allow for growth on prefered carbohydrates (such as glucose) in the presence of other non-prefered sugars. The description of this research can be found in J. Mol. Biol.

Postdoctoral Research

I did my postdoctoral work in the laboratories of Drs. Bart Hazes and Laura Frost, both at the Univeristy of Alberta. My research focused on two systems. The first system under investigation was aimed at correlating protein structure and biological activity of type IV pilins. Bacteria such as Pseudomonas aeruginosa use pili, which are fibrous assemblies of pilin monomers, in cellular adhesion during infection. Therefore, understanding the structure of the pilins can shed insight into their biological function. The ultimate goal of this project is to develop effective anti-bacterial agents with which to combat P. aeruginosa infection. My interests in the type IV pilins continue, as through the course of my research I identified the generation of protein nanotubes from the engineered pilin monomers.

The second area of research was focused on the process of bacterial conjugation, using the F-plasmid conjugative system of Escherichia coli. Conjugation is a plasmid-driven process by which bacteria can transfer genetic material, such as genes required for antibiotic resistance, among a bacterial population. The aim of this research is to couple a detailed structural understanding of the proteins involved in F-plasmid conjugation with detailed biochemical data to provide a clearer understanding of the conjugative process. I continue to focus on stuctural investigations of the F-plasmid system in collaboration with Dr. Laura Frost.

 

 

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