# Nonequilibrium phases of a biomolecular condensate facilitated by enzyme activity

## TL;DR

This paper shows how enzyme activity and RNA interactions create dynamic, nonequilibrium states in biomolecular condensates, which are important for cellular organization.

## Contribution

The study reveals a new mechanism where DEAD-box helicase activity and RNA base-pairing drive nonequilibrium phases in condensates.

## Key findings

- DEAD-box helicase activity continuously remodels RNA interactions in condensates.
- RNA secondary structure and helicase activity have an antagonistic relationship that maintains condensate homogeneity.
- Condensate properties like partitioning and morphology evolve over time due to enzyme activity.

## Abstract

Biomolecular condensates represent a frontier in cellular organization, existing as dynamic macromolecular structures driven out of equilibrium by active cellular processes. Here we explore active mechanisms of condensate regulation by examining the interplay between DEAD-box helicase activity and RNA base-pairing interactions within a reconstituted ribonucleoprotein condensate. We demonstrate that the ATP-dependent activity of a DEAD-box helicase—a key class of enzymes in condensate regulation—acts as a nonequilibrium driver of condensate properties through the continuous remodeling of RNA interactions. By combining the LAF-1 DEAD-box helicase with a designer RNA hairpin concatemer, we unveil a complex landscape of dynamic behaviors, including time-dependent alterations in RNA partitioning, evolving condensate morphologies, and shifting condensate dynamics. Importantly, we reveal an antagonistic relationship between RNA secondary structure and helicase activity which enables an initially homogeneous nonequilibrium state. By elucidating these nonequilibrium mechanisms, we gain a deeper understanding of cellular organization and expand the potential for active synthetic condensate systems.

Energy-dependent helicase activity and RNA secondary structure work together to preserve an initial nonequilibrium state of condensate homogeneity and dynamics.