Micro-Raman spectroscopic analysis of liquid-liquid phase separation

Area of Science:

• Biophysics
• Molecular Biology
• Biochemistry

Background:

• Liquid-liquid phase separation (LLPS) is crucial for cellular organization and disease.
• Understanding LLPS molecular mechanisms, especially protein aggregation, is vital for disease insights.
• Current methods lack detailed structural information within liquid droplets.

Purpose of the Study:

• To investigate the molecular mechanisms of LLPS and protein fibrillation.
• To characterize structural changes within protein droplets during LLPS.
• To explore the role of water's hydration environment in LLPS.

Main Methods:

• Utilized micro-Raman spectroscopy combined with differential interference contrast (DIC) microscopy.
• Monitored protein conformational changes and water hydrogen-bonding (H-bonding) structure.
• Analyzed the O-D stretching band of water (HOD in H2O) within droplets.

Main Results:

• Observed distinct Raman spectra for water inside droplets compared to bulk water.
• Demonstrated that the hydration environment within protein droplets changes over time during LLPS.
• Showcased the capability of micro-Raman spectroscopy to study dynamic processes within droplets.

Conclusions:

• Micro-Raman spectroscopy provides high spatial resolution for studying LLPS.
• This technique can elucidate molecular mechanisms linking LLPS to protein aggregation and amyloid formation.
• The study highlights the importance of the water hydration environment in LLPS.