Research

I have a background in inorganic chemistry. Dubois’s lab is involved in much more biochemistry and bioinorganic chemistry. I have spent the first months learning many biochemistry techniques.
Then I started to work with Bennett Streit on Chlorite dismutase enzyme and I am now trying to understand how this enzyme is works. Chlorite dismutase is a heme b and it carries out the heme-catalyzed decomposition of ClO2- to Cl-. These anions are known water contaminants.
 Heme b enzymes have a variety of biological functions including  catalyzing oxidation/reduction reactions, small molecule sensing and transport, as well as electron transport.  While they all share similar active site heme groups  they have distinctly different reactivities with the configurations of their active sites often specifying the reactivity at the heme center. While other catalytic histidine ligated heme b enzymes, such as Horseradish peroxidase (HRP), cytochrome c peroxidase (CCP), and Arthromyces ramosus peroxidase  (ARP), are capable of utilizing ClO2- as an oxidant for catalysis only Cld catalyzes the stoichiometric decomposition of chlorite. During the summer, I made a mutant of this enzyme. Like many peroxidases, Cld has at its active site a proximal and distal pocket. I mutated the aspartic acid residue on the proximal pocket to an asparagine residue. This mutation should break the hydrogen bond between the COOH  of the aspartic acid residue and Histidine residue. A careful study of the enzyme’s and its mutant steady state kinetics has been carried out and in the process I have learned molecular biology techniques.
The future objectives then are to make others mutants to have more information in order to compare the wild type Cld to other peroxidases like CCP or HrP. We would like to use some resonance raman or EPR in order to have a better understanding of these mutants
For now, Cld acts as a poor peroxidase.
I am interested in also studying perchlorate reductase. Perchlorate reductase is a molybdopterin-dependent enzyme that is proposed to catalyze the successive reduction of ClO4- to ClO3-,water contaminants.
Because of my background, I’m really interested in working with nanoparticles. Nanoparticles are of great scientific interest as they are effectively a bridge between bulk materials and atomic or molecular structures. I really would like to find a way to work with an enzyme (possibly Cld) and nanoparticles.

Publications

Niki Baccile, Julien Reboul, Blanc Beatrice and Corine Gerardin, Ecodesign of Ordered Mesoporous Materials Obtained with Switchable Micellar Assemblies, Angewandte chemie, 2008

B. R. Streit, B. Blanc, G. S. Lukat-Rodgers, K. R. Lukat-Rodgers, J. L. Dubois, How active site protonation state influences the reactivity and ligation of the heme in chlorite dismutase, JACS, 2010, 132, 5711-5724