# Spatiotemporal organization of membrane protein controls bacterial extracellular electron transfer

## TL;DR

The study reveals how protein organization in bacteria enables electron transfer, a key process for energy conversion and biotechnology.

## Contribution

The study identifies CymA protein reorganization as a novel mechanism for enabling bacterial extracellular electron transfer.

## Key findings

- CymA protein forms localized regions during active electron transfer in Shewanella oneidensis.
- CymA reorganization is linked to biomolecular condensate formation and facilitates electron partner colocalization.
- Electron transfer efficiency is critically dependent on CymA spatial dynamics and membrane domain interactions.

## Abstract

Extracellular electron transfer (EET) is essential for electroactive microbes’ physiology and biotechnological applications. Many such microbes are Gram-negative bacteria, in which EET must cross two membranes and the periplasm, necessitating spatial and temporal collaborations of various EET proteins that reside at different cellular compartments, for which little is known. Using single-molecule/single-cell-level fluorescence microscopy and electrochemical manipulations, we discover that in the electroactive bacterium Shewanella oneidensis, the inner-membrane electron-transfer hub protein CymA undergoes spatial reorganization into localized regions during active EET with dispersed formation dynamics, subsequently driving the colocalization of its direct electron-transfer partners in the periplasm. Correlated single-cell-level photoelectrochemistry-fluorescence microscopy further proves the critical function of CymA reorganization in enabling EET. A multitude of evidence suggests that CymA reorganization stems from biomolecular condensate formation, likely initiated by association with menaquinone-rich inner-membrane domains. These orchestrated spatiotemporal protein dynamics extend the functional roles of biomolecular condensates to include facilitation of EET in bacteria, with broader implications for cellular processes.

Extracellular electron transfer (EET) in bacteria requires the spatiotemporal coordination of many proteins. Here, authors show that the inner-membrane protein CymA reorganizes spatially into condensates and drives the colocalization of partner proteins to enable EET in Shewanella.