Mass-sensitive particle tracking to elucidate the membrane-associated MinDE reaction cycle

Area of Science:

• Biophysics
• Cell Biology
• Biochemistry

Background:

• Studying molecular interactions on biological membranes is crucial but challenging due to limited methods.
• Mass photometry offers potential for quantifying unlabeled biomolecules on surfaces.

Purpose of the Study:

• To develop and validate a novel method for analyzing single unlabeled biomolecules on supported lipid bilayers.
• To apply this method to investigate the self-organization dynamics of bacterial MinDE proteins.

Main Methods:

• Developed a new interferometric scattering (iSCAT) image processing and analysis strategy for diffusing particles.
• Enabled mass-sensitive particle tracking (MSPT) of single, unlabeled biomolecules on supported lipid bilayers.
• Applied MSPT to study the MinDE protein system.

Main Results:

• Successfully tracked and quantified individual membrane-bound MinD/MinDE protein complexes.
• Determined the stoichiometry and turnover rates of these complexes.
• Quantified the size-dependent diffusion of membrane-associated protein complexes.

Conclusions:

• MSPT is a powerful technique for studying membrane-associated biological systems at the single-molecule level.
• This method provides quantitative insights into the dynamics and stoichiometry of membrane protein complexes.
• The findings enhance the understanding of protein self-organization on biological membranes.