Related Experiment Video
Updated: Jun 21, 2026

Translating Extracellular Electron Transfer Activities with Organic Electrochemical Transistors
Published on: January 31, 2025
Short-chain chromate ion transporter proteins from Bacillus subtilis confer chromate resistance in Escherichia coli
Amada Díaz-Magaña1, Esther Aguilar-Barajas, Rafael Moreno-Sánchez
1Instituto de Investigaciones Químico-Biológicas, Universidad Michoacana, Morelia, Michoacán.
Abstract:
Tandem paired genes encoding putative short-chain monodomain protein members of the chromate ion transporter (CHR) superfamily (ywrB and ywrA) were cloned from genomic DNA of Bacillus subtilis strain 168. The transcription of the paired genes, renamed chr3N and chr3C, respectively, was shown to occur via a bicistronic mRNA generated from a promoter upstream of the chr3N gene. The chr3N and chr3C genes conferred chromate resistance when expressed in Escherichia coli strain W3110. The cloned chr3N gene alone did not confer chromate resistance on E. coli, suggesting that both chr3N and chr3C genes are required for function. E. coli cells expressing paired chr3N and chr3C genes demonstrated diminished uptake of chromate compared to that by a vector-only control strain. These results suggest that short-chain CHR proteins form heterodimer transporters which efflux chromate ions from the cytoplasm.
Related Concept Videos
Chemotaxis in E. coli
ABC Transporters: Importer
In bacteria, based on the number of transmembrane helices and the chemical nature of their substrates, the ABC importers can be divided into three types:
Stringent Response in E. coli
ABC Transporters: Exporter
Electron Transport Chain Components

