The hydrodynamic motion of Nanodiscs.

Area of Science:

• Biophysics
• Biochemistry
• Structural Biology

Background:

• Nanodiscs are crucial for studying membrane protein-lipid interactions.
• Understanding Nanodisc dynamics is key to interpreting these interactions.
• Current methods for monitoring Nanodisc dynamics are limited.

Purpose of the Study:

• To develop a fluorescence-based method for monitoring Nanodisc rotational dynamics.
• To investigate the relationship between Nanodisc size and rotational correlation time.
• To establish a foundation for label-free quantification of membrane protein-lipid interactions.

Main Methods:

• Utilized a long-lifetime Ruthenium fluorescent label attached to Nanodiscs.
• Varied Nanodisc diameter by adjusting the membrane scaffold protein (MSP) helical repeats.
• Employed analytical spheroid models and numerical atomic models for simulation.

Main Results:

• Observed increasing rotational correlation times with increasing Nanodisc diameter.
• Demonstrated a linear correlation between experimental and calculated rotational times.
• Validated the fluorescence methodology against theoretical models.

Conclusions:

• The developed method accurately quantifies Nanodisc rotational dynamics.
• Nanodisc size directly influences its rotational behavior.
• This work paves the way for precise, label-free analysis of membrane protein-lipid interactions.