2026-07-22T09:51:02Zhttps://repisalud.isciii.es/rest/oai/request

oai:repisalud.isciii.es:20.500.12105/263532025-12-18T12:59:56Zcom_20.500.12105_2052com_20.500.12105_2051col_20.500.12105_19617

00925njm 22002777a 4500 dc Dubach, Victor R A author Segundo-Acosta, Pablo San author Murphy, Bonnie J author 2024-11 Nicotinamide adenine dinucleotide phosphate (NADPH) oxidases (NOXs) have a major role in the physiology of eukaryotic cells by mediating reactive oxygen species production. Evolutionarily distant proteins with the NOX catalytic core have been found in bacteria, including Streptococcus pneumoniae NOX (SpNOX), which is proposed as a model for studying NOXs because of its high activity and stability in detergent micelles. We present here cryo-electron microscopy structures of substrate-free and nicotinamide adenine dinucleotide (NADH)-bound SpNOX and of NADPH-bound wild-type and F397A SpNOX under turnover conditions. These high-resolution structures provide insights into the electron-transfer pathway and reveal a hydride-transfer mechanism regulated by the displacement of F397. We conducted structure-guided mutagenesis and biochemical analyses that explain the absence of substrate specificity toward NADPH and suggest the mechanism behind constitutive activity. Our study presents the structural basis underlying SpNOX enzymatic activity and sheds light on its potential in vivo function. Dubach VRA, San Segundo-Acosta P, Murphy BJ. Structural and mechanistic insights into Streptococcus pneumoniae NADPH oxidase. Nat Struct Mol Biol. 2024 Nov;31(11):1769-1777. 10.1038/s41594-024-01348-w 1545-9985 1545-9993 Nature structural and molecular biology 39039317 https://hdl.handle.net/20.500.12105/26353 Structural and mechanistic insights into Streptococcus pneumoniae NADPH oxidase