Native Mass Spectrometry of Membrane Protein-Lipid Interactions in Different Detergent Environments

Area of Science:

• Biochemistry
• Structural Biology
• Mass Spectrometry

Background:

• Native mass spectrometry (MS) is crucial for studying membrane protein structure and function.
• Detergents used in MS can cause protein unfolding, hindering the study of protein-lipid interactions.
• Investigating protein-lipid interactions in different detergent environments is essential.

Purpose of the Study:

• To demonstrate the use of charge-reducing molecules with native MS for studying protein-lipid interactions.
• To investigate how different detergents and charge-reducing molecules affect lipid binding to membrane proteins.
• To characterize lipid interactions with the bacterial water channel (AqpZ) and ammonia channel (AmtB) complexed with GlnK.

Main Methods:

• Native mass spectrometry (MS) with charge-reducing molecules (spermine, trimethylamine-N-oxide).
• Utilized bacterial water channel (AqpZ) and ammonia channel (AmtB) complexed with GlnK.
• Employed a fluorescent lipid binding assay.

Main Results:

• Charge-reducing molecules facilitate the characterization of lipid binding in various detergents.
• Protein-lipid interactions are dependent on the specific protein, detergent, and charge-reducing molecule used.
• AqpZ-lipid interactions were enhanced in LDAO, while AmtB-GlnK interactions were similar across detergents.
• Fluorescent lipid binding assay results corroborated native MS findings regarding detergent dependence.

Conclusions:

• Native MS, enhanced by charge-reducing molecules, is a powerful tool for optimizing experimental conditions for studying protein-lipid interactions.
• This approach is valuable for drug discovery and biochemical/structural investigations of membrane proteins.
• Understanding detergent effects is critical for accurate characterization of membrane protein-lipid dynamics.