Structural characterization of the enterococcal polysaccharide antigen and analysis of its contribution to cell growth, division and antibiotic resist

点击翻译按钮获取中文摘要

The proposed project is focused on the functional analysis of a surfacerhamnopolysaccharide produced by all enterococci, required for normal cell growth,division, resistance to antibiotics and pathogenesis. This enterococcal polysaccharideantigen (EPA) is encoded by two gene clusters: (i) 18 genes extremely conserved (epaA-epaR) encoding a core synthetic machinery and (ii) 10-20 genes variable from one strain toanother, responsible for the decoration of the polysaccharide backbone. We have built amutant with a complete deletion of the epa variable region and shown that the decoration ofEPA (but not its core structure) is essential for the biological activity of this polymer. Wepropose investigate the structural properties of Epa and dissect the specific contribution ofthis polymer and its decoration to bacterial physiology and antibiotic resistance.We will take a multidisciplinary approach to explore EPA structure and to understand howEPA controls the distribution and activity of surface proteins involved in cell wall assemblyand resistance to antibiotics. The project will involve state-of-the-art methodologiesincluding super-resolution microscopy (fluorescence and electron microscopy), structuralglycobiology (NMR, mass spectrometry) and conventional approaches to study bacterialphysiology and antimicrobial resistance. The candidate will work with members of thesupervisors' laboratories studying bacterial cell surface assembly and host-pathogeninteractions.