Zinc(II) tolerance in Escherichia coli K‐12: evidence that the zntA gene (o732) encodes a cation transport ATPase

Beard, Steven J.; Hashim, Rohani; Membrillo-Hernández, Jorge; Hughes, Martin N.; Poole, Robert K.

doi:10.1111/j.1365-2958.1997.mmi518.x

Cited by 175 publications

(144 citation statements)

References 41 publications

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“…7 Therefore, multiple zinc specific transport systems maintain homeostasis in the cell. In eubacteria, zinc uptake is facilitated by the ZnuABC 8 and ZupT 9 transport systems and zinc efflux is maintained by the ZntA, 10 ZitB, 11 and ZntB 12 efflux systems.…”

Section: Introductionmentioning

confidence: 99%

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

et al. 2009

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ZntB is the distant homolog of CorA Mg 21 transporter within the metal ion transporter superfamily. It was early reported that the ZntB from Salmonella typhimurium facilitated efflux of Zn 21 and Cd 21 , but not Mg 21 . Here, we report the 1.90 Å crystal structure of the intracellular domain of ZntB from Vibrio parahemolyticus. The domain forms a funnel-shaped homopentamer that is similar to the full-length CorA from Thermatoga maritima, but differs from two previously reported dimeric structures of truncated CorA intracellular domains. However, no Zn 21 or Cd 21 binding sites were identified in the high-resolution structure. Instead, 25 well-defined Cl 2 ions were observed and some of these binding sites are highly conserved within the ZntB family. Continuum electrostatics calculations suggest that the central pore of the funnel is highly attractive for cations, especially divalents. The presence of the bound Cl 2 ions increases the stability of cations along the pore suggesting they could be important in enhancing cation transport.

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Section: Introductionmentioning

confidence: 99%

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

et al. 2009

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“…Therefore, most cells have to regulate the intracellular concentration over a small range by a certain membrane transport mechanism. In Escherichia coli, an export system for zinc and other divalent cations has already been identified (2). But in S. aureus, although membrane transport systems for heavy metals have been well investigated, most of them, such as the cad system (27) for cadmium and the ars system (16) for arsenic, are encoded on plasmid and are therefore not specific for zinc.…”

mentioning

confidence: 99%

Chromosome‐Determined Zinc‐Responsible Operon czr in Staphylococcus aureus Strain 912

Kuroda

Hayashi

Ohta

1999

Microbiology and Immunology

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A novel operon, czrAB (zinc-responsible genes), was identified in the chromosome of Staphylococcus aureus. The operon consists of two genes, czrA and czrB. The czrA gene, coding for an 11.5 kDa protein, was homologous to cadC, arsR of S. aureus plasmid pI258 and smtB of Synechococcus PCC7942. The czrB, coding for a 36 kDa membrane spanning protein, was homologous to the czcD gene, cobalt, zinc and the cadmium-resistant factor of Bacillus subtilis and Alcaligenes eutrophus. In the presence of zinc (0.1-10 mM), the transcription of czrAB was enhanced in a concentration-dependent manner. Other heavy metals, such as cobalt, copper, manganese and nickel showed no effect on czrAB expression. The disruptant of the czrB gene became sensitive to zinc ion (MIC, 2 mM; MBC, 10 mM), and the complementation with the plasmid recovered the resistance to zinc at the same concentration as a parental strain (MIC, 5 mM; MBC, 20 mM). The disruptant accumulated intracellular zinc up to 0.4 mg per g dry weight of the organism, while that of the parental strain was 0.25 mg per g dry weight. The findings indicated that the novel operon czrAB should play a role in the transportation of zinc across the cell membrane to maintain the proper intracellular concentration.

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“…Copper-transporting CPx-type ATPases have been described in bacteria, including cyanobacteria (21,22), S. cerevisiae, higher plants, and man; representatives of this protein family (reviewed in Ref. 23) are also known that transport cadmium (24), zinc and lead (25)(26)(27), silver (28), and cobalt (29). We recently described two such copper transporters in Synechocystis PCC 6803, CtaA and PacS, both of which are required for efficient switching to the use of copper in plastocyanin rather than heme iron in cytochrome c 6 for photosynthetic electron transport (15).…”

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confidence: 99%

A Copper Metallochaperone for Photosynthesis and Respiration Reveals Metal-specific Targets, Interaction with an Importer, and Alternative Sites for Copper Acquisition

Tottey¹,

Rondet²,

Borrelly³

et al. 2002

Journal of Biological Chemistry

147

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A bacterial two-hybrid assay revealed interaction between a protein now designated bacterial Atx1 and amino-terminal domains of copper-transporting ATPases CtaA (cellular import) and PacS (thylakoid import) but not the related zinc (ZiaA) or cobalt (CoaT) transporters from the same organism (Synechocystis PCC 6803). The specificity of metallochaperone interactions coincides with metal specificity. After reconstitution in a N 2 atmosphere, bacterial Atx1 bound 1 mol of copper mol ؊1 , and apoPacS N acquired copper from copper-Atx1. Copper was displaced from Atx1 by p-(hydroxymercuri)phenylsulfonate, indicative of thiol ligands, and two cysteine residues were obligatory for two-hybrid interaction with PacS N . This organism contains compartments (thylakoids) where the copper proteins plastocyanin and cytochrome oxidase reside. In copper super-supplemented mutants, photooxidation of cytochrome c 6 was greater in ⌬atx1⌬ctaA than in ⌬ctaA, showing that Atx1 contributes to efficient switching from iron in cytochrome c 6 to copper in plastocyanin for photosynthetic electron transport. Cytochrome oxidase activity was also less in membranes purified from low [copper]-grown ⌬atx1 or ⌬pacS, compared with wild-type, but the double mutant ⌬atx1⌬pacS was non-additive, consistent with Atx1 acting via PacS. Conversely, activity in ⌬atx1⌬ctaA was less than in either respective single mutant, revealing that Atx1 can function without the major copper importer and consistent with a role in recycling endogenous copper.

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Zinc(II) tolerance in Escherichia coli K‐12: evidence that the zntA gene (o732) encodes a cation transport ATPase

Abstract: Summary

Cited by 175 publications

References 41 publications

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

Structure and electrostatic property of cytoplasmic domain of ZntB transporter

Chromosome‐Determined Zinc‐Responsible Operon czr in Staphylococcus aureus Strain 912

A Copper Metallochaperone for Photosynthesis and Respiration Reveals Metal-specific Targets, Interaction with an Importer, and Alternative Sites for Copper Acquisition

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