Dynamic Variation in Protein-Small Molecule Interaction Observed by Double-Nanohole Optical Trapping

TL;DR

This study demonstrates that double-nanohole optical trapping can observe real-time, single-molecule interactions between proteins and small molecules, revealing distinct dynamic behaviors without surface tethering or external markers.

Contribution

It introduces a novel application of double-nanohole optical trapping to monitor protein-small molecule interactions at the single-molecule level in real time.

Findings

Distinct trapping behaviors observed with and without small molecule binding

Real-time dynamics accessible at the single protein level

Technique does not require tethering or exogenous markers

Abstract

The interaction of proteins with small molecules is fundamental to their function in living organisms and it is widely studied in drug development. Here we compare optical trapping dynamics of streptavidin and biotinylated streptavidin using a double nanohole optical trap in a metal film. Consistent and clearly distinct behavior is seen between the protein with and without the small molecule binding. The real-time dynamics at the single protein level are accessible with this technique, which also has advantages of not requiring tethering to a surface or the need for exogeneous markers.