Aligned peptoid-based macrodiscs for structural studies of membrane proteins by oriented-sample NMR

Area of Science:

• Biophysics
• Biochemistry
• Materials Science

Background:

• Solid-state NMR requires uniform lipid mimetics for macroscopically aligned membrane proteins.
• Existing methods like bicelles and styrene-maleic acid polymers have limitations in uniformity and composition.

Purpose of the Study:

• To develop a novel, robust, uniform, and magnetically orientable lipid mimetic for advanced solid-state NMR.
• To evaluate the performance of peptoid-based macrodiscs compared to conventional lipid mimetics.

Main Methods:

• Synthesis of 15-residue peptoid oligomers with alternating N-(2-phenethyl)glycine and N-(2-carboxyethyl)glycine residues.
• Incorporation of Pf1 coat protein into the peptoid-based macrodiscs.
• Solid-state NMR spectroscopy to analyze protein alignment and membrane structure.

Main Results:

• Peptoid-based macrodiscs exhibit lower polydispersity, resulting in highly uniform discs.
• NMR spectra show a higher order parameter and uniform linewidths for membrane proteins in peptoid discs compared to bicelles and peptide-based macrodiscs.
• The peptoid mimetics are detergent-free, offering an advantage over traditional bicelles.

Conclusions:

• Peptoid-based macrodiscs represent a superior lipid mimetic for solid-state NMR of membrane proteins.
• This novel approach facilitates enhanced protein alignment and detailed structural analysis.
• The detergent-free nature of peptoid discs simplifies sample preparation and improves data quality.