ESR imaging of myelin basic protein induced vesicle aggregation

Area of Science:

• Biophysics
• Materials Science
• Biochemistry

Background:

• Phospholipid vesicles are crucial model systems for cell membranes.
• Myelin basic protein (MBP) interactions with lipids are vital in neurological function.
• Understanding these interactions requires high-resolution imaging techniques.

Purpose of the Study:

• To develop and apply advanced Electron Spin Resonance (ESR) imaging for high-resolution analysis of lipid-protein interactions.
• To quantitatively compare the sedimentation characteristics of different phospholipid vesicles.
• To investigate the effect of myelin basic protein on vesicle aggregation and molecular mass.

Main Methods:

• Utilized modulated magnetic field gradient technique for ESR spectroscopy and imaging.
• Recorded ESR spectra and 1D-ESR images of spin-labeled stearic acid in phospholipid vesicles.
• Employed pelleting of vesicles in capillaries followed by centrifugation.
• Analyzed sedimentation profiles using ESR imaging to determine effective molecular mass.

Main Results:

• Achieved spatial resolution of 4.10(-5) m for ESR imaging of vesicles.
• Quantitatively compared sedimentation of dimyristoylphosphatidylcholine and dimyristoylphosphatidylglycerol vesicles.
• Observed and quantified vesicle aggregation induced by myelin basic protein.
• Determined protein-induced changes in effective molecular mass from ESR images.

Conclusions:

• ESR imaging provides a powerful tool for studying lipid-protein interactions at high resolution.
• Myelin basic protein induces significant changes in vesicle aggregation and molecular mass.
• Data strongly suggest that acidic lipids are the primary target for MBP-lipid interactions in myelin.