Degradation of cellulose by lytic polysaccharide monooxygenases
Jeudi 19 novembre 2015 10:00
- Duree : 1 heure
Lieu : CIBB Seminar Room, ILL - 71 avenue des Martyrs - Grenoble
Orateur : Luisa CIANO (University of York (UK))
The effective use of biomass is crucial in addressing the global need for alternative and sustainable energy sources. One of the major challenges for the utilisation of cellulose and other polysaccharides as starting materials for biofuel and commodity chemical synthesis is the recalcitrance of these materials to degradation. Bacteria and fungi have overcome this problem by producing a wide arsenal of enzymes able to effectively degrade cellulose, chitin and lignin. Much effort has been directed by several research groups worldwide, particularly in recent years, to try and understand the molecular mechanism behind enzymatic polysaccharide degradation, to then exploit these enzymes in industrial processes.
A major breakthrough in this field was achieved in 2010/11 with the discovery of a new class of enzymes called lytic polysaccharide monooxygenases (LPMOs). LPMOs are copper containing oxygenases characterised by a highly conserved active site which incorporates a motif referred to as the “histidine brace”, in which a single copper is coordinated by the imidazole rings of two histidine residues and the N-terminus of the protein. LPMOs utilise atmospheric oxygen, a reductant, and the copper co-factor to oxidise the glycosidic C-H bond, breaking the polysaccharide chain and boosting the activity of canonical glycoside hydrolases.
The talk will highlight recent developments in the understanding of the mechanism of action of these enzymes, with a focus on X-ray crystallography and electron paramagnetic spectroscopy (EPR) to gain information about substrate degradation and reactive species involved in the oxidative process.
Contact : deme@ill.fr
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