[SCAN] Insights on the flavodiiron NO reductase from Escherichia coli

Title: Insights on the flavodiiron NO reductase from Escherichia coli

Speaker: Filipe Folgosa

Abstract: Molecules such as O₂ and NO and their reactive species (ROS and RNS) are extremely important to living organisms. In mammals, ROS and RNS play an important role in the protection mechanisms against pathogens. To be able to survive to those stress conditions during colonization, defense mechanisms evolved in microorganisms, namely pathogens, in order to enable them to cope with these molecules. One of these mechanisms is based on flavodiiron proteins, FDPs. Widespread among all Kingdoms, from bacteria to higher organisms, FDPs are capable of tackling NO detoxification, contributing to the microbial survival to the stress imposed by the host immune system. FDPs are enzymes with a minimal core of two domains: a metallo-β-lactamase-like domain, harboring the catalytic diiron center, and a flavodoxin-like, FMN containing, domains.

Escherichia coli encodes in its genome one flavodiiron protein with the two canonical domains and an extra rubredoxin-like one. So far, the FDP from E. coli is the only one known to have NO as its preferential substrate, converting it into the innocuous N2O.

We thoroughly studied a series of site-directed mutants in a highly conserved region among the FDPs in order to identify their effect in the catalytic activity of the E. coli FDP. Our results showed that some of the mutants under study presented a dramatic effect in the ability to reduce NO.

ITQB NOVA Virtual Auditorium

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