Fañanás, Elisa Millana Todesca, Sofia Sicorello, Alessandro Masino, Laura Pompach, Petr Magnani, Francesca Pastore, Annalisa Mattevi, Andrea On the mechanism of calcium-dependent activation of NADPH oxidase 5 (NOX5). It is now accepted that reactive oxygen species (ROS) are not only dangerous oxidative agents but also chemical mediators of the redox cell signaling and innate immune response. A central role in ROS-controlled production is played by the NADPH oxidases (NOXs), a group of seven membrane-bound enzymes (NOX1-5 and DUOX1-2) whose unique function is to produce ROS. Here, we describe the regulation of NOX5, a widespread family member present in cyanobacteria, protists, plants, fungi, and the animal kingdom. We show that the calmodulin-like regulatory EF-domain of NOX5 is partially unfolded and detached from the rest of the protein in the absence of calcium. In the presence of calcium, the C-terminal lobe of the EF-domain acquires an ordered and more compact structure that enables its binding to the enzyme dehydrogenase (DH) domain. Our spectroscopic and mutagenesis studies further identified a set of conserved aspartate residues in the DH domain that are essential for NOX5 activation. Altogether, our work shows that calcium induces an unfolded-to-folded transition of the EF-domain that promotes direct interaction with a conserved regulatory region, resulting in NOX5 activation. EF-hands;NMR;calcium activation;enzyme;structure;SB;NMR-ack;Biochemistry & Molecular Biology;0601 Biochemistry and Cell Biology;1101 Medical Biochemistry and Metabolomics;0304 Medicinal and Biomolecular Chemistry 2020-07-01
    https://crick.figshare.com/articles/journal_contribution/On_the_mechanism_of_calcium-dependent_activation_of_NADPH_oxidase_5_NOX5_/12571178