Dupont Claude

Biography

Professor Claude Dupont graduated from B.Sc. in Biochemistry (1984) and M.Sc. in Environmental Sciences (1986) from the University of Quebec at Trois-Rivières . In 1991, he obtained a Ph.D. from the University of Guelph , Ontario, for his work on the characterization and biosynthesis of the peptidoglycan "O-acetylation" phenomenon in Proteus mirabilis. He then worked as an 18-month postdoctoral fellow at the Chemistry Department of the Carlsberg Laboratory (Copenhagen, Denmark) where he worked on the study of mechanism of action and structure / function relationships of Aspergillus niger glucoamylase. He was a NSERC fellow for one year at the Center for Food and Zootechnical Research, (Ottawa), where he worked on the expression of synthesized proteins de novo and then became professor at the INRS-Institut Armand-Frappier in September 1993.

Research Interest

Structure / Function Study of Streptomyces lividans xylanase A The resolution of the three-dimensional structure of the xylanase A catalytic domain of S. lividans by X-ray crystallography made it possible to demonstrate the role of several amino acids in the catalysis, binding or specificity of enzyme to its substrate. Following this analysis, an extensive xylanase A engineering program, using site-directed mutagenesis, was undertaken and is currently underway. The objectives of this program are: 1. identify the amino acids involved in the active site of the enzyme and establish their roles and functions; 2. modify, by site-directed mutagenesis, xylanase A to produce an enzyme capable of operating at extreme temperatures (85-100oC) and alkaline pH (9-11); 3. to establish the rules governing the stability of enzymes with a (alpha / beta) 8 folding pattern using xylanase A as a model. Characterization of Streptomyces lividans hemicellulases Hemicellulases are found in several genera and species of microorganisms and are responsible for the degradation of hemicelluloses, including xylan, the major compounds of lignocellulolitic biomass. The complete degradation of xylan requires the action of several different enzymes (xylanases, acetyl-xylan esterases, arabinofuranosidases, glucoronidases, ß-xylosidases), enzymes that are produced in Streptomyces lividans. They are enzymes with applications in several industrial fields (pulp and paper, food, energy). Understanding the mode of action of these enzymes is therefore a priority in order to be able, by genetic engineering, to produce enzymes meeting the industry specifications. The biotechnology research group for sreptomycetes, of the IAF, has cloned and characterized many of these enzymes in the past and is continuing its efforts to discover new enzymes. These enzymes are subjected to complete biochemical, physicochemical and kinetic characterization in order to establish their physiological functions and roles.