Analysis tools for single-monomer measurements of self-assembly processes

Area of Science:

• Biochemistry and Biophysics
• Molecular Biology
• Cellular Dynamics

Background:

• Protein assembly, including aggregation and polymerization, is crucial for cellular function and implicated in diseases.
• Single-molecule techniques offer powerful ways to study protein assembly dynamics.
• Analyzing single-filament data requires robust and validated methodologies.

Purpose of the Study:

• To develop and validate novel analysis methods for single-filament protein assembly data.
• To compare the performance of new methods (visitation and average-rate analysis) against traditional dwell-time analysis.
• To investigate the impact of experimental parameters on data analysis.

Main Methods:

• Development of visitation analysis and average-rate analysis for single-filament data.
• Benchmarking and comparison with classic dwell-time analysis.
• Testing analysis limitations concerning signal-to-noise ratio, sampling rate, and dye properties (labeling efficiency, bleaching rate).

Main Results:

• The developed visitation and average-rate analyses provide robust tools for single-filament data interpretation.
• Comparison revealed the strengths and limitations of each analysis method under varying experimental conditions.
• Application to actin assembly showed Cappuccino promotes fast elongation without nucleation, while Spire's WH2 motifs do not induce de novo nucleation.

Conclusions:

• Novel analysis methods enhance the study of single-molecule protein assembly.
• Understanding the limitations of analysis methods is critical for accurate interpretation of experimental data.
• The study provides new mechanistic insights into actin assembly regulated by Cappuccino and Spire.