# Quantitative Connection Between Ensemble Thermodynamics and Single-Molecule Kinetics: A Case Study Using Cryogenic Electron Microscopy and Single-Molecule Fluorescence Resonance Energy Transfer Investigations of the Ribosome

## TL;DR

This paper introduces a framework linking static ensemble thermodynamic data with dynamic single-molecule kinetic data, demonstrated through cryo-EM and smFRET studies of the ribosome, enhancing understanding of energy landscapes.

## Contribution

A generalized dwell-time based framework connecting ensemble thermodynamics with single-molecule kinetics, applied to ribosomal studies to clarify conformational observations.

## Key findings

- Framework explains discrepancies between cryo-EM and smFRET conformations.
- Application reveals why certain transient states are observed in cryo-EM but not in smFRET.
- Enhances interpretation of energy landscapes in biomolecular systems.

## Abstract

At equilibrium, thermodynamic and kinetic information can be extracted from biomolecular energy landscapes by many techniques. However, while static, ensemble techniques yield thermodynamic data, often only dynamic, single-molecule techniques can yield the kinetic data that describes transition-state energy barriers. Here we present a generalized framework based upon dwell-time distributions that can be used to connect such static, ensemble techniques with dynamic, single-molecule techniques, and thus characterize energy landscapes to greater resolutions. We demonstrate the utility of this framework by applying it to cryogenic electron microscopy (cryo-EM) and single-molecule fluorescence resonance energy transfer (smFRET) studies of the bacterial ribosomal pre-translocation complex. Among other benefits, application of this framework to these data explains why two transient, intermediate conformations of the pre-translocation complex, which are observed in a cryo-EM study, may not be observed in several smFRET studies.