# Tetramethylrhodamine self-quenching is a probe of conformational change on the scale of 15–25 Å

## TL;DR

This study shows that tetramethylrhodamine self-quenching can detect small conformational changes in biological molecules over distances of 15–25 Å.

## Contribution

The paper validates TMR self-quenching as a reliable alternative to FRET for measuring conformational changes.

## Key findings

- TMR self-quenching is distance-dependent and sensitive to conformational changes of 15–25 Å.
- The timescale of TMR dissociation was characterized to support its use in biological assays.
- Spectroscopic analysis confirmed the reliability of TMR as a conformational probe.

## Abstract

Tetramethylrhodamine (TMR) is a fluorescent dye whose self-quenching has been used as a probe of multiple biological phenomena. We determine the distance-dependence of self-quenching and place bounds on the timescale of TMR dissociation. Our results validate fluorescence self-quenching as an alternative to FRET and enable future assays to be designed with confidence.

Tetramethylrhodamine (TMR) self-quenching is validated as a probe of small conformational change in biological macromolecules by distance-dependence, timescale and spectroscopic characterisation.