Using the reversible inhibition of gastric lipase by Orlistat for investigating simultaneously lipase adsorption and substrate hydrolysis at the lipid–water interface

International audienc

An interfacial and comparative in vitro study of gastrointestinal lipases and Yarrowia lipolytica LIP2 lipase, a candidate for enzyme replacement therapy

International audienc

New insights into the pH-dependent interfacial adsorption of dog gastric lipase using the monolayer technique

International audienc

Fatty Acid Photodecarboxylase Is an Interfacial Enzyme That Binds to Lipid–Water Interfaces to Access Its Insoluble Substrate

International audienceFatty Acid Photodecarboxylase (FAP), one of the few natural photoenzymes characterized so far, is a promising biocatalyst for lipid-to-hydrocarbon conversion using light. However, the optimum supramolecular organization under which the fatty acid (FA) substrate should be presented to FAP has not been addressed. Using palmitic acid embedded in phospholipid liposomes, phospholipid-stabilized microemulsions and mixed micelles, we show that FAP displays a preference for FAs present in liposomes and at the surface of microemulsions. Adsorption kinetics onto phospholipid and galactolipid monomolecular films further suggests the ability of FAP to bind to and penetrate into membranes, with higher affinity in the presence of FAs. FAP structure reveals a potential interfacial recognition site with clusters of hydrophobic and basic residues surrounding the active site entrance. The resulting dipolar moment suggests the orientation of FAP at negatively charged interfaces. These findings provide important clues for the mode of action of FAP and the development of FAP-based bioconversion processes

Effects of the propeptide of group X secreted phospholipase A2 on substrate specificity and interfacial activity on phospholipid monolayers

International audienc

Biochemical and structural characterization of non-glycosylated Yarrowia lipolytica LIP2 lipase

International audienc

Solution conformational features and interfacial properties of an intrinsically disordered peptide coupled to alkyl chains: a new class of peptide amphiphiles

International audienc

Solution conformational features and interfacial properties of an intrinsically disordered peptide coupled to alkyl chains: a new class of peptide amphiphiles

International audienc

Cyclipostins and Cyclophostin Analogs as Promising Compounds in the Fight Against Tuberculosis

A new class of Cyclophostin and Cyclipostins (CyC) analogs have been investigated against Mycobacterium tuberculosis H37Rv (M. tb) grown either in broth medium or inside macrophages. Our compounds displayed a diversity of action by acting either on extracellular M. tb bacterial growth only, or both intracellularly on infected macrophages as well as extracellularly on bacterial growth with very low toxicity towards host macrophages. Among the eight potential CyCs identified, CyC 17 exhibited the best extracellular antitubercular activity (MIC50 = 500 nM). This compound was selected and further used in a competitive labelling/enrichment assay against the activity-based probe Desthiobiotin-FP in order to identify its putative target(s). This approach, combined with mass spectrometry, identified 23 potential candidates, most of them being serine or cysteine enzymes involved in M. tb lipid metabolism and/or in cell wall biosynthesis. Among them, Ag85A, CaeA and HsaD, have previously been reported as essential for in vitro growth of M. tb and/or survival and persistence in macrophages. Overall, our findings support the assumption that CyC 17 may thus represent a novel class of multi-target inhibitor leading to the arrest of M. tb growth through a cumulative inhibition of a large number of Ser- and Cys-containing enzymes participating in important physiological processes

Influence of lipid packing on the membrane-binding properties of mycolactone.

<p>Change in surface pressure (Δπ, mN/m) when mycolactone interacts with mixed monolayers at different initial surface pressures (π_i, mN/m). The nature of the lipid membrane was as follows: (A) and (B) mixture 1 consisting of 39% POPC, 33% SM, 9% POPE, 19% Chol. (C) and (D) mixture 2 consisting of 48% POPC, 41% SM, 11% POPE (given in mol%). Experiments were performed at 20°C (A) and (C), or 25°C (B) and (D). Each point corresponds to an independent measurement with a new lipid monolayer formed on PBS subphase (pH 7.4). The final concentration of mycolactone was 60 nM. Representative data from two or three independent assays are shown.</p