Yes / Exploring the detailed structural features of synthetic molecules in the membrane phase requires sensitive probes of conformation. Here we describe the design, synthesis and characterization of bis(pyrene) probes that report conformational changes in membrane-active dynamic foldamers. The probes were designed to distinguish between left-handed (M) and right-handed (P) screw-sense conformers of 310-helical α-aminoisobutyric acid (Aib) peptide foldamers, both in solution and in bilayer membranes. Several different bis(pyrene) probes were synthesized and ligated to the C-terminus of Aib tetramers that had different chiral residues at the N-terminus, residues that favored either an M or a P screw-sense in the 310-helix. The readily synthesized and conveniently incorporated N-acetyl-1,2-bis(pyren-1′-yl)ethylenediamine probe proved to have the best properties. In solution, changes in foldamer screw-sense induced substantial changes in the ratio of excimer/monomer fluorescence emission (E/M) for this reporter of conformation, with X-ray crystallography revealing that opposite screw-senses produce very different interpyrene distances in the reporter. In bilayers, this convenient and sensitive fluorescent reporter allowed, for the first time, an investigation of how the chirality of natural phospholipids affects foldamer conformation. / European Research Council (Advanced Grant ROCOCO), the BBSRC (DTP studentship and grant BB/I007962) and the EPRSC (grants EP/N009134/1 and EP/ K039547).

Les micropolluants d'origine pharmaceutique tels que les antibiotiques, les hormones, les anti-inflammatoires ou les médicaments anticancéreux sont généralement réfractaires aux procédés classiques de traitement des eaux et leur rejet dans l'environnement même à l'état de traces (< µg/L) pose de réels problèmes environnementaux et de santé publique. Le traitement de ces effluents par voie enzymatique semble être une alternative intéressante et ce d'autant plus si le biocatalyseur est immobilisé directement à la surface d'une membrane afin d'améliorer sa stabilité et permettre sa réutilisation. Le travail à réaliser dans le cadre de cette thèse vise la conception et l'optimisation de bioréacteurs destinés à la dégradation de micropolluants ciblés. Réalisé dans le cadre d'un contrat Européen (ENDETECH), ce travail est une collaboration avec d'autres équipes de recherche européennes en charge de sélectionner les biocatalyseurs et de mettre au point les méthodes analytiques de détection et de caractérisation des produits de la réaction. / Pharmaceutical micropollutants such as antibiotics, hormones, anti-inflammatory or anti-cancer drugs are usually reluctant to conventional wastewater treatment processes and their disposal in the environment, even at low concentrations (< µg/L) may have an impact on human health. The enzymatic treatment of these effluents seems a promising alternative if the biocatalyst is immobilized on a membrane to enhance its stability and to enable its reuse. This thesis work aims at designing and optimizing bioreactors for micropollutants degradation. It is a collaboration (ENDETECH project) with other European research teams in charge of selecting the biocatalysts and developing analytical methods for the detection and characterization of transformation products.