The unit’s main project is the elaboration of specific, sensitive and performing methodologies for the identification and the characterization of proteins, peptides and other peptidomimetic molecules such as toxins. Protein analysis in proteomic studies generally combine separation techniques such gel electrophoresis and chromatography to mass spectrometry. MALDI-TOF/TOF MS detection (Matrix Assisted Laser Desorption Ionisation–Time Of Flight) has been widely developed to achieve peptide mapping and sequencing. The MALDI ionization mode can be employed in tissue imaging by localizing specific molecules such as peptides and proteins directly from tissue slices or cells, both healthy and pathological, in order to demonstrate the presence of certain bio-markers for example.
However, the emergence of liquid nano-chromatographic techniques in both one (1D-LC) and two-dimensional (2D-LC) configurations coupled to high resolution high accuracy tandem mass spectrometers (MS/MS), such as hybrid instruments like QqOT (Quadripole-Orbitrap) or ion trap LIT-FTICR (Linear Ion Trap-Fourier Transform Ion Cyclotron Resonance) is a powerful alternative. This attractive approach offers the capacity to fragment peptides that are present in very small amounts, in order to obtain amino acid sequence information. This coupling allows the skipping of the 2D-GE separation step. The characterization of all the proteins as well as their post-translational modifications is directly performed from the mixture.
We have shown that MALDI ionization can also be coupled to MS/MS analysis in order to generate sequence information directly from preparations having served to establish peptide maps for example, and also to identify and characterized post-translational modifications such as glycosylation or redox modifications. Indeed, we developed a specific know how around redoxomics strategies to study the proteins redox state in the cells. Lately we have been involved in different techniques for quantitative analysis, using label free or isotopic labelling. This can be efficiently combined with targeted analysis to reach high sensitivity and specificity.
Plateform of mass spectrometry and proteomics(english)
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