Missions

Spectroscopic and mechanistic studies of peptide models of LPMO enzymes.

Activités

Lignocellulosic biomass is increasingly considered as a renewable feedstock to produce bio-sourced chemicals, biomaterials and advanced biofuels. In this context, Copper-dependent Lytic Polysaccharide Monooxygenases (Cu-LPMO), discovered in 2010, have attracted attention given their ability to initiate the degradation of recalcitrant polysaccharides from biomass. LPMO are mono-copper enzymes able to promote extended polysaccharides cleavage (e.g. cellulose or chitin) using oxidative mechanisms. More precisely, LPMO catalyze the hydroxylation of an inert C-H bond at the glycosidic linkage (either at C1 or C4 position) at the surface of recalcitrant polysaccharide polymers further leading to glycosidic bond cleavage.

A new and promising research line in the host team is the design, structural and functional study of bioinspired catalysts. In this context, we have recently started to structurally and functionally characterized peptide-based models of Cu-LPMO. The peptide scaffold chosen, although quite simple in design, is able to reproduce the key features of the Cu(II) coordination site and the Cu-peptide complexes thus obtained show promising activity towards a model substrate. The aim of the project is to widen the peptide families, with rationale modifications to improve the catalytic activity of the Cu-peptide complexes.

1) Peptide synthesis
- Peptide synthesis carried out on a microwave-assisted robot,
- Recovery of raw peptides from the resin,
- Purification of peptides by chromatographic purification: flash chromatography, HPLC-MS in semi-preparative and preparative modes.
- Quality control of synthesized peptides: HPLC, NMR, MS.
- Participation in peptide synthesizer maintenance.

2) Implementation of oxidation screening studies on model substrates (cellobiose, non-polysaccharide model substrates) using UV-Vis and Fluorescence monitoring.
-Preparation of samples to be studied
-Drafting of study protocol (one experiment corresponds to the screening of several experimental conditions)
-Program and maintain analyzers (spectrometers)
-Check that data acquisition is running smoothly
-Data analysis
-Writing a report for each experiment and presenting results at team meetings and conferences

3) Spectroscopic and analytical studies of oxidative mechanisms using UV-Vis, EPR, NMR, IR, circular dichroism, fluorescence and electrochemistry.
-Formatting of acquired data in a spreadsheet and analysis of the data obtained.
-Writing of a report for each experiment and presentation of results at team meetings and conferences.

Working as part of a team

Compétences

- Excellent skills in bioinorganic chemistry, analytical chemistry and peptide chemistry,
- Solid experience in physico-chemical and biochemical analyses, particularly spectroscopic (UV-Vis and fluorescence),
Knowledge of solid-state peptide synthesis is a plus,
- Proficiency in general computer tools (Office) and those specific to the field (Kaleidagraph).
- Organization and management of work time to ensure experiments are carried out within defined deadlines.
- Ability to work as part of a team.

Contexte de travail

The work will be carried out mainly at the CNRS Coordination Chemistry Laboratory (UPR 8241) in the “Alzheimer's, Amyloid and Bio-Inorganic Chemistry” team led by Dr. Christelle Hureau.

Contraintes et risques

Handling of chemicals.

Informations complémentaires

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