# Structural dynamics of protein-protein association involved in the light-induced transition of Avena sativa LOV2 protein

## TL;DR

This paper uses X-ray techniques to study how light causes a protein from oat plants to form dimers, revealing key structural changes and interactions.

## Contribution

The study provides novel structural insights into light-induced dimerization of LOV2 proteins using time-resolved X-ray liquidography.

## Key findings

- Dimerization occurs within milliseconds after unfolding of the A’α and Jα helices.
- Protein-protein interactions among β-scaffolds, mediated by helix unfolding, are key to dimerization.
- The work offers mechanistic insights into PPI-driven oligomerization in LOV2 proteins.

## Abstract

The Light-oxygen-voltage-sensing domain (LOV) superfamily, found in enzymes and signal transduction proteins, plays a crucial role in converting light signals into structural signals, mediating various biological mechanisms. While time-resolved spectroscopic studies have revealed the dynamics of the LOV-domain chromophore’s electronic structures, understanding the structural changes in the protein moiety, particularly regarding light-induced dimerization, remains challenging. Here, we utilize time-resolved X-ray liquidography to capture the light-induced dimerization of Avena sativa LOV2. Our analysis unveils that dimerization occurs within milliseconds after the unfolding of the A’α and Jα helices in the microsecond time range. Notably, our findings suggest that protein-protein interactions (PPIs) among the β-scaffolds, mediated by helix unfolding, play a key role in dimerization. In this work, we offer structural insights into the dimerization of LOV2 proteins following structural changes in the A’α and Jα helices, as well as mechanistic insights into the protein-protein association process driven by PPIs.

Here, the authors provide mechanistic insight into light-induced dimerization of a Light-Oxygen-Voltage (LOV) domain using time-resolved X-ray liquidography, furthering our understanding LOV domain photoactivation and protein-protein interaction-driven oligomerization.