Native Desorption Electrospray Ionization Liberates Soluble and Membrane Protein Complexes from Surfaces

Area of Science:

• Analytical Chemistry
• Biochemistry
• Mass Spectrometry

Background:

• Traditional mass spectrometry for intact protein complexes relies on electrospray ionization.
• Direct desorption from surfaces for intact protein complexes using mass spectrometry has not been achieved.
• Desorption Electrospray Ionization (DESI) MS has been effective for analyzing small molecules on tissue surfaces.

Purpose of the Study:

• To develop a native DESI MS platform for analyzing intact protein complexes.
• To enable high-throughput screening of ligand binding to protein targets.
• To overcome limitations of current MS techniques for studying protein complexes.

Main Methods:

• Development of a native DESI MS platform preserving non-covalent interactions.
• Utilizing the surface for capturing enzyme-substrate complexes.
• Optimizing detergents for membrane protein analysis.
• Demonstrating ligand binding to membrane proteins and GPCRs.

Main Results:

• Successful capture of a rapid turnover enzyme-substrate complex.
• Optimization of detergents for studying membrane proteins.
• Demonstration of lipid and drug binding to membrane proteins.
• Selective binding of agonists to a G protein-coupled receptor (GPCR) from a mixture.

Conclusions:

• The developed native DESI MS platform facilitates the study of intact protein complexes.
• This platform has potential for high-throughput ligand screening of challenging drug targets, including GPCRs.
• It offers a new approach for analyzing non-covalent interactions and ligand binding.