# Selective benefit of the sucrose TonB-dependent receptor, SucA, in Caulobacter crescentus

## TL;DR

This paper investigates the function of the SucA protein in Caulobacter crescentus, showing when it provides a growth advantage and how it works.

## Contribution

The study identifies specific conditions where the SucA TBDR provides a measurable fitness benefit and confirms its reliance on the proton motive force.

## Key findings

- SucA provides a significant growth advantage under specific environmental conditions.
- SucA activity depends on the proton motive force, consistent with canonical TBDR function.

## Abstract

Gram-negative bacteria have outer membrane proteins called TonB-dependent receptors (TBDRs) that facilitate energy-dependent transport of substrates.
Caulobacter crescentus
is a gram-negative bacterium with a large set of TBDRs, yet the function of many of these TBDRs remains uncharacterized. This study focuses on SucA, a TBDR that transports sucrose. Previous studies showed that
sucA
expression was induced in the presence of sucrose, yet did not provide a measurable fitness advantage under the conditions tested. This work identifies conditions where
sucA
does confer a significant growth advantage and provides evidence that SucA activity relies on the proton motive force, a feature of canonical TBDRs.