# Simulating Freely Diffusing Single-Molecule FRET Data with Consideration of Protein Conformational Dynamics

## TL;DR

This paper introduces a simulation method for single-molecule FRET experiments that incorporates protein conformational dynamics and molecular diffusion.

## Contribution

A new simulation framework integrating conformational dynamics and photon emission statistics for realistic smFRET data.

## Key findings

- Langevin dynamics can generate interdye distance distributions for simulating freely diffusing smFRET data.
- The module enables validation of analysis techniques for conformationally flexible biomolecules.
- Molecular dynamics simulations can enhance the realism of the simulated data.

## Abstract

Single-molecule Förster
resonance energy transfer (smFRET)
experiments have greatly contributed to the understanding of the conformational
dynamics of proteins and other biomolecules. Generating high-fidelity
simulated data for smFRET experiments is an important step toward
developing and examining accurate and efficient smFRET data analysis
techniques. Here, we use distributions of interdye distances generated
using Langevin dynamics to simulate freely diffusing smFRET timestamp
data for proteins and biomolecules that have conformational flexibility.
We then compare analysis techniques for smFRET data to validate the
new module. The Langevin dynamics is used here as an illustrative
example to demonstrate how modeling conformational dynamics can be
integrated with molecular diffusion and photon emission statistics,
all of which are essential for realistic simulation of freely diffusing
smFRET data. We also discuss different ways to generalize our approach
to make the simulated data more realistic including the employment
of molecular dynamics (MD) simulations that is illustrated with an
example. The Langevin dynamics module provides a framework for generating
timestamp data for systems with a known underlying conformational
heterogeneity as a step toward the development of new analysis techniques
for smFRET data dealing with flexible proteins or other biomolecular
systems.