Simultaneous acquisition of 2D and 3D solid-state NMR experiments for sequential assignment of oriented membrane...

Area of Science:

• Biophysical Chemistry
• Structural Biology
• Nuclear Magnetic Resonance (NMR) Spectroscopy

Background:

• Solid-state NMR is crucial for determining membrane protein structures.
• Simultaneous acquisition of multiple NMR spectra can improve efficiency.
• Sequential assignment of membrane proteins remains challenging.

Purpose of the Study:

• To introduce DAISY (Dual Acquisition Oriented ssNMR spectroScopY), a novel method for simultaneous 2D and 3D oriented solid-state NMR.
• To enable efficient acquisition of complementary NMR spectra for membrane protein analysis.
• To facilitate the sequential assignment of membrane proteins.

Main Methods:

• DAISY utilizes dual acquisition of sine and cosine coherences.
• It employs long-living (15)N longitudinal polarization for enhanced signal.
• The method integrates PISEMA (Polarization Inversion Spin Exchange at the Magic Angle) or HETCOR (Heteronuclear Correlation) sequences with mixing elements for inter-residue correlations.

Main Results:

• DAISY simultaneously acquires two sets of 2D spectra (e.g., PISEMA and PISEMA-mixing, or HETCOR and HETCOR-mixing).
• The method allows for the distinction of (15)N-(15)N inter-residue correlations.
• DAISY was successfully implemented in 3D experiments, acquiring 3D PISEMAI-HETCOR and 3D PISEMAI-HETCOR-mixing simultaneously.

Conclusions:

• DAISY significantly enhances the efficiency of oriented solid-state NMR experiments.
• The method provides a robust approach for the sequential assignment of membrane proteins.
• DAISY offers a valuable tool for structural studies of membrane proteins in aligned lipid bilayers.