[SCAN] Miguel Teixeira

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Title: The mosaic structure of flavodiiron O2/NO reductases: how to combat oxidative and nitrosative stresses

Speaker: Miguel Teixeira

Affiliation: Metalloenzymes and Molecular Bioenergetics Lab, ITQB NOVA

Abstract:

Oxygen by itself is a toxic species. Therefore, organisms that are exposed to oxygen in their environment, or produce it endogenously (oxygenic organisms), as well as anaerobes that either in the external environment or inside the host are exposed transiently to deadly concentrations of O2, are endowed with enzymes to directly reduce it to water. Apart from the well-known respiratory and membrane bound oxygen reductases, a family of cytoplasmatic enzymes exists that is able to convert O2 into H2O. These enzymes - the flavodiiron proteins (FDPs)- contribute to combat oxidative stress by, simultaneously, eliminating oxygen and, indirectly, decreasing the formation of reactive oxygen species. FDPs have the capability of reducing O2 to water and/or NO to the innocuous N2O. Flavodiiron proteins are widespread in the three life Kingdoms and are metalloenzymes having as the minimal core unit a diiron-containing and an FMN containing domains, although much more complex FDPs are encountered in the microbial world, having a diversity of extra iron- and flavin- containing modules. I shall discuss our latest results on FDPs from the human pathogens, E. coli and Clostridium difficile