Interdomain Flexibility within NADPH Oxidase Suggested by SANS Using LMNG Stealth Carrier

Area of Science:

• Biophysics
• Structural Biology
• Biochemistry

Background:

• Integral membrane proteins (IMPs) are crucial but challenging targets for structural determination.
• Small angle neutron scattering (SANS) offers a method for low-resolution structural information of IMPs.
• Streptococcus pneumoniae NADPH oxidase (SpNOX) serves as a prokaryotic model for eukaryotic NOX enzymes.

Purpose of the Study:

• To determine the structural envelope of SpNOX using SANS.
• To develop a cost-effective SANS approach for IMP structural analysis.
• To characterize the overall structure of a NOX enzyme.

Main Methods:

• Solubilization of SpNOX using lauryl maltose neopentyl glycol detergent.
• Application of Small Angle Neutron Scattering (SANS) with specifically deuterated protein and solvent.
• Integration of SANS data with molecular modeling.

Main Results:

• The detergent was experimentally undetected in SANS due to specific deuteration.
• A structural envelope of the SpNOX enzyme was determined.
• The determined structure was less compact than predicted, suggesting a flexible linker between domains.

Conclusions:

• SANS with deuterated components provides a cost-effective method for IMP structural studies.
• This study presents the first structural characterization of an entire NOX enzyme.
• The findings reveal insights into the structural flexibility of NOX enzymes.