Quantitative spectroscopy of single molecule interaction times

TL;DR

This paper develops a theoretical framework for analyzing single molecule interaction times using fluorescence tracking, revealing how interaction time distributions transition from power law to exponential behavior and depend on microscopic reaction rates.

Contribution

It introduces a novel spectroscopy method for quantifying molecule interaction times and provides a theoretical foundation validated by simulations and experiments.

Findings

Distribution of interaction times transitions from power law to exponential.

Exponential decay depends on the product of microscopic reaction rates.

Method validated on both simulated and experimental data.

Abstract

Single molecule fluorescence tracking provides information at nm-scale and ms-temporal resolution about the dynamics and interaction of individual molecules in a biological environment. While the dynamic behavior of isolated molecules can be characterized well, the quantitative insight is more limited when interactions between two indistinguishable molecules occur. We address here this aspect by developing a solid theoretical foundation for a spectroscopy of interaction times, i.e. the inference of interaction constants from imaging data. The non trivial crossover between a power law to an exponential behavior of the distribution of the interaction times is highlighted here, together with the dependence of the exponential term upon the product of the microscopic reaction rates (affinity). Our approach is validated on simulated as well as experimental datasets.