8QT9

Cryo-EM structure of stably reduced Streptococcus pneumoniae NADPH oxidase in complex with NADH

Summary for 8QT9

• Entry DOI: 10.2210/pdb8qt9/pdb
• EMDB information: 18646
• Descriptor: FAD-binding FR-type domain-containing protein, FLAVIN-ADENINE DINUCLEOTIDE, PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• Functional Keywords: nadph oxidase, ros producing, flavoprotein, heme protein, membrane protein
• Biological source: Streptococcus pneumoniae
• Total number of polymer chains: 1
• Total formula weight: 48744.52

Authors

Dubach, V.R.A.,San Segundo-Acosta, P.,Murphy, B.J. (deposition date: 2023-10-12, release date: 2024-07-24, Last modification date: 2024-07-31)

Primary citation

Dubach, V.R.A.,San Segundo-Acosta, P.,Murphy, B.J.
Structural and mechanistic insights into Streptococcus pneumoniae NADPH oxidase.
Nat.Struct.Mol.Biol., 2024

PubMed Abstract: 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.

PubMed: 39039317
DOI: 10.1038/s41594-024-01348-w

Experimental method

ELECTRON MICROSCOPY (2.36 Å)