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RcnB Is a Periplasmic Protein Essential for Maintaining Intracellular Ni and Co Concentrations in Escherichia coli
- Source :
- Journal of Bacteriology, Journal of Bacteriology, American Society for Microbiology, 2011, 193 (15), pp.3785-3793. ⟨10.1128/JB.05032-11⟩
- Publication Year :
- 2011
- Publisher :
- American Society for Microbiology, 2011.
-
Abstract
- Nickel and cobalt are both essential trace elements that are toxic when present in excess. The main resistance mechanism that bacteria use to overcome this toxicity is the efflux of these cations out of the cytoplasm. RND (resistance-nodulation-cell division)- and MFS (major facilitator superfamily)-type efflux systems are known to export either nickel or cobalt. The RcnA efflux pump, which belongs to a unique family, is responsible for the detoxification of Ni and Co in Escherichia coli . In this work, the role of the gene yohN , which is located downstream of rcnA , is investigated. yohN is cotranscribed with rcnA , and its expression is induced by Ni and Co. Surprisingly, in contrast to the effect of deleting rcnA , deletion of yohN conferred enhanced resistance to Ni and Co in E. coli , accompanied by decreased metal accumulation. We show that YohN is localized to the periplasm and does not bind Ni or Co ions directly. Physiological and genetic experiments demonstrate that YohN is not involved in Ni import. YohN is conserved among proteobacteria and belongs to a new family of proteins; consequently, yohN has been renamed rcnB. We show that the enhanced resistance of rcnB mutants to Ni and Co and their decreased Ni and Co intracellular accumulation are linked to the greater efflux of these ions in the absence of rcnB . Taken together, these results suggest that RcnB is required to maintain metal ion homeostasis, in conjunction with the efflux pump RcnA, presumably by modulating RcnA-mediated export of Ni and Co to avoid excess efflux of Ni and Co ions via an unknown novel mechanism.
- Subjects :
- HOMEOSTASIS
EFFLUX
Physiology and Metabolism
Mutant
ATP-binding cassette transporter
Biology
medicine.disease_cause
Microbiology
03 medical and health sciences
Copper Transport Proteins
Nickel
[CHIM.ANAL]Chemical Sciences/Analytical chemistry
BINDING
Escherichia coli
medicine
COBALT
[SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology
Cation Transport Proteins
Molecular Biology
030304 developmental biology
Metal ion homeostasis
0303 health sciences
METAL RESISTANCE
030306 microbiology
Escherichia coli Proteins
ABC TRANSPORTER
Biological Transport
Periplasmic space
ANAEROBIC GROWTH
Major facilitator superfamily
Transport protein
NICKEL TRANSPORTER NIKA
MUTANTS
Biochemistry
Biophysics
Efflux
Periplasmic Proteins
SYSTEM
Subjects
Details
- ISSN :
- 10985530 and 00219193
- Volume :
- 193
- Database :
- OpenAIRE
- Journal :
- Journal of Bacteriology
- Accession number :
- edsair.doi.dedup.....60261f7fc98c5156d6ba1c58dee3ffc3