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NC State Biochemistry



Flora Meilleur
Associate Professor of Biochemistry

PhD: European Molecular Biology Laboratory, Heidelberg (Germany)
Postdoctoral: The Institut Laue Langevin, Grenoble (France)

Office: 148 Polk Hall
   ORNL Office: 865.576.2779
   Cell: 865.242.5747
Email: Flora Meilleur

Flora Meilleur

Website: Visit our Lab Home Page

Research Areas: cellulose degrading enzymes, cytochrome P450s, X-ray and neutron structural biochemistry, mechanistic enzymology biochemistry, mechanistic enzymology

Research in my lab focusses on cellulose degrading enzymes. The enzymatic degradation of cellulose remains one of the key challenges to be overcome in biofuel production. Understanding how wood-degrading-organism enzymes function is required to guide enzyme engineering and design more efficient enzymes. Two types of extracellular enzymatic systems have been identified in microorganisms capable of cellulose degradation: a hydrolytic system comprising hydrolases responsible for cellulose and hemicellulose degradation and an oxidative ligninolytic system which depolymerizes lignin. Effort in my lab is focused on gaining insight into the structures and degradation mechanisms of enzymes from both systems and into the protein interactions between the two systems.

My lab is also interested in understanding cytochrome P450s, one of nature's most versatile biologic catalysts. Cytochromes P450 (P450s) are ubiquitous enzymes catalyzing monooxygenation reactions and playing diverse functional roles in a broad range of biological systems. In mammals they are involved in a variety of biochemical processes including carcinogenesis, drug metabolism, biosynthesis of lipids and steroids or degradation of xenobiotics.

Currently, our research focuses on cytochrome P450cam (CYP101) from the soil bacteria Pseudomonal putida, the model system of the P450 superfamily. The hydrogen shuttle pathway occurring at the active site during monooxygenation catalysis is a matter of debate. The enhanced visibility of hydrogen and of its deuterium isotope in neutron protein structures suggests that neutron protein crystallography could provide critical information that could help further characterize the proton transfer in the P450cam enzymatic mechanism. The neutron analysis is further extended to putidaredoxin (Pdx) and putidaredoxin reductase (Pdr), the P450cam redox partners, to characterize the two-electron transfer from Pdr to P450cam and through Pdx leading to the activation of the final P450cam component in this monooxygenase system.

Small-angle neutron scattering (SANS) with contrast variation is ideally suited to the study of large, nested, multi-density, and spherical systems such as viruses in solution. The application of contrast variation makes it possible to highlight different structural elements, thereby understanding the assembly of the whole particle.

My lab uses primarily a combination of X-ray and neutron diffraction and scattering.

Keywords: cytochrome P450s, glycoside hydrolases, lytic polysaccharide monooxygenases, cellobiose dehydrogenases, hydrogen bond networks, protonation states, protein–protein interactions, multi-domain proteins, crystallography, small angle scattering, X-ray, neutrons