E-type delayed fluorescence depolarization, technique to probe rotational motion in the microsecond range

Area of Science:

• Biophysics
• Biochemistry
• Membrane Protein Dynamics

Background:

• Investigating slow rotational movement of macromolecules like membrane proteins requires techniques with extended time ranges.
• Existing methods may not adequately cover the microsecond to millisecond timescale for rotational diffusion.

Purpose of the Study:

• To extend the time range for measuring rotational diffusion to microseconds and milliseconds.
• To enable the investigation of slow rotational movement of macromolecules, such as membrane proteins.
• To describe an apparatus for determining time-dependent anisotropy in this time range.

Main Methods:

• Utilizing eosin (E)-type delayed fluorescence depolarization.
• Measuring time-dependent anisotropy.
• Employing an apparatus designed for microsecond to millisecond timescales.

Main Results:

• Eosin-type delayed fluorescence depolarization successfully extends the measurement time range for rotational diffusion.
• The method allows for the investigation of slow rotational movement of macromolecules.
• The described apparatus is suitable for determining time-dependent anisotropy in the microsecond to millisecond range.

Conclusions:

• Eosin-type delayed fluorescence depolarization is a valuable technique for studying slow macromolecular rotational dynamics.
• The developed apparatus effectively measures time-dependent anisotropy in the microsecond to millisecond range.
• The method was validated using eosin-labelled cytochrome P-450 in phospholipid membrane vesicles.