# Remolding laccase for whole-cell and in vivo modulation of dopamine signal

## TL;DR

Scientists redesigned a bacterial enzyme to regulate dopamine signals in the brain without harmful byproducts, offering a new way to treat dopamine-related disorders.

## Contribution

A redesigned laccase enzyme with a Ru-Cu binuclear center enables efficient dopamine catabolism without reactive oxygen species.

## Key findings

- The remolded laccase shows up to tenfold higher physiological activity compared to native laccase.
- The enzyme enables whole-cell down-regulation of dopamine and erasure of extracellular dopamine signals in intact brains.
- A self-adaptive catalytic mechanism was revealed through structural and computational studies.

## Abstract

Biocatalytic regulation of dopamine signals paves an effective and biocompatible way to modulate dopaminergic functions and disorders. Here, we report the remolding of bacterial laccase, catalyzing conversions of dopamine and O2 to o-quinone and H2O, into a biocatalytic neuromodulator by reactive oxygen species–free dopamine catabolism. Given the poor activity of native laccase in the physiological context because of OH− inhibition of its geometrically constrained O2-reducing center, we designed a highly dynamic Ru-Cu binuclear center to counteract the inhibition effect. Structural and computational investigations unravel a self-adaptive catalytic mechanism by reversive Ru-Cu active site reconfiguration that lowers the kinetic barriers for O2-to-H2O conversion in neutral solution. The remolded laccase exhibits substantial enhancement of physiological activity (up to one order of magnitude) and improved catecholamine substrate specificity, enabling whole-cell down-regulation of vesicular dopamine and extracellular erasure of evoked dopamine signals in intact brains. Our work elucidates a picture of artificial metalloenzymes for neuromodulation through a rationalized neurotransmitter metabolism pathway.

An artificial metalloenzyme catalyzing ROS-free dopamine oxidation is designed for multilevel neuromodulation.