Roles of Agrobacterium tumefaciens C58 ZntA and ZntB and the transcriptional regulator ZntR in controlling Cd2+/Zn2+/Co2+ resistance and the peroxide stress response

Chaoprasid, Paweena; Nookabkaew, Sumontha; Sukchawalit, Rojana; Mongkolsuk, Skorn

doi:10.1099/mic.0.000135

Cited by 18 publications

(17 citation statements)

References 59 publications

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“…Interestingly, the analysis of regulation of ZntB expression in C. metallidurans revealed that it was downregulated in the presence of high concentrations of Zn 2+ , Cd 2+ and Cu 2+ 6 , which suggests that it is an importer, rather than an exporter. Additionally the expression of homologous ZntB from Agrobacterium tumefaciens was not induced by treatments with Zn 2+ in a range from 100 to 750 µM 36 . Our experiments show that ZntB most likely mediates Zn 2+ /H + co-transport, and thus indicate that ZntB is an importer for zinc.…”

Section: Discussionmentioning

confidence: 95%

The structural basis of proton driven zinc transport by ZntB

et al. 2017

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Zinc is an essential microelement to sustain all forms of life. However, excess of zinc is toxic, therefore dedicated import, export and storage proteins for tight regulation of the zinc concentration have evolved. In Enterobacteriaceae, several membrane transporters are involved in zinc homeostasis and linked to virulence. ZntB has been proposed to play a role in the export of zinc, but the transport mechanism of ZntB is poorly understood and based only on experimental characterization of its distant homologue CorA magnesium channel. Here, we report the cryo-electron microscopy structure of full-length ZntB from Escherichia coli together with the results of isothermal titration calorimetry, and radio-ligand uptake and fluorescent transport assays on ZntB reconstituted into liposomes. Our results show that ZntB mediates Zn2+ uptake, stimulated by a pH gradient across the membrane, using a transport mechanism that does not resemble the one proposed for homologous CorA channels.

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Section: Discussionmentioning

confidence: 95%

The structural basis of proton driven zinc transport by ZntB

et al. 2017

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“…6C. Intracellular zinc levels are sensed by two transcriptional regulators, Zur and ZntR (25,61). Zur is a repressor in the Fur family, whereas ZntR is an activator belonging to the MerR family.…”

Section: Discussionmentioning

confidence: 99%

Agrobacterium tumefaciens Zur Regulates the High-Affinity Zinc Uptake System TroCBA and the Putative Metal Chaperone YciC, along with ZinT and ZnuABC, for Survival under Zinc-Limiting Conditions

Chaoprasid

Dokpikul

Johnrod

et al. 2016

Appl Environ Microbiol

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Agrobacterium tumefaciens has a cluster of genes (Atu3178, Atu3179, and Atu3180) encoding an ABC-type transporter, here named troA, troB, and troC, respectively, which is shown here to be a zinc-specific uptake system. Reverse transcription (RT)-PCR analysis confirmed that troA, troB, and troC are cotranscribed, with troC as the first gene of the operon. The yciC (Atu3181) gene is transcribed in the opposite orientation to that of the troCBA operon and belongs to a metal-binding GTPase family. Expression of troCBA and yciC was inducible under zinc-limiting conditions and was controlled by the zinc uptake regulator, Zur. Compared to the wild type, the mutant strain lacking troC was hypersensitive to a metal chelator, EDTA, and the phenotype could be rescued by the addition of zinc, while the strain with a single yciC mutation showed no phenotype. However, yciC was important for survival under zinc limitation when either troC or zinT was inactivated. The periplasmic zinc-binding protein, ZinT, could not function when TroC was inactivated, suggesting that ZinT may interact with TroCBA in zinc uptake. Unlike many other bacteria, the ABC-type transporter ZnuABC was not the major zinc uptake system in A. tumefaciens. However, the important role of A. tumefaciens ZnuABC was revealed when TroCBA was impaired. The strain containing double mutations in the znuA and troC genes exhibited a growth defect in minimal medium. A. tumefaciens requires cooperation of zinc uptake systems and zinc chaperones, including TroCBA, ZnuABC, ZinT, and YciC, for survival under a wide range of zinc-limiting conditions. IMPORTANCEBoth host and pathogen battle over access to essential metals, including zinc. In low-zinc environments, physiological responses that make it possible to acquire enough zinc are important for bacterial survival and could determine the outcome of hostpathogen interactions. A. tumefaciens was found to operate a novel pathway for zinc uptake in which ZinT functions in concert with the high-affinity zinc importer TroCBA. Zinc is an essential metal for bacteria because it is required for the functions of many enzymes and proteins (1, 2). However, zinc overload is toxic to cells (3-7). Bacteria have mechanisms to maintain zinc homeostasis via the coordinated response of genes involved in zinc uptake, efflux, and storage (8-13). The zinc uptake regulator Zur is a transcriptional regulator belonging to the Fur family and functions as a repressor of zinc uptake genes, including znuABC and zinT (10). To prevent excessive amounts of zinc in cells under high-zinc conditions, Zur uses Zn 2ϩ as its cofactor to bind to a conserved AT-rich sequence, called the Zur box (14), found in the promoter region of the zinc uptake genes, leading to inhibition of gene expression (15)(16)(17). ZnuA is a periplasmic protein that binds zinc and transfers it to the membrane permease ZnuB and the ATPase ZnuC (15). The ZinT protein is a periplasmic zinc-binding protein (18-21) that has been shown to directly interact with and assist ZnuABC i...

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“…It is believed that ZntA (See Zn section) may also play a role in the efflux cobalt (Chaoprasid et al . 2015 ) (Fig. 2 ).…”

Section: Introductionmentioning

confidence: 97%

An overview ofSalmonella entericametal homeostasis pathways during infection

Cunrath

Palmer

2021

microLife

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Nutritional immunity is a powerful strategy at the core of the battlefield between host survival and pathogen proliferation. A host can prevent pathogens from accessing biological metals such as Mg, Fe, Zn, Mn, Cu, Co or Ni, or actively intoxicate them with metal overload. While the importance of metal homeostasis for the enteric pathogen Salmonella enterica Typhimurium was demonstrated many decades ago, inconsistent results across various mouse models, diverse Salmonella genotypes, and differing infection routes challenge aspects of our understanding of this phenomenon. With expanding access to CRISPR-Cas9 for host genome manipulation, it is now pertinent to re-visit past results in the context of specific mouse models, identify gaps and incongruities in current knowledge landscape of Salmonella homeostasis, and recommend a straight path forward towards a more universal understanding of this historic host-microbe relationship.

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Roles of Agrobacterium tumefaciens C58 ZntA and ZntB and the transcriptional regulator ZntR in controlling Cd2+/Zn2+/Co2+ resistance and the peroxide stress response

Cited by 18 publications

References 59 publications

The structural basis of proton driven zinc transport by ZntB

The structural basis of proton driven zinc transport by ZntB

Agrobacterium tumefaciens Zur Regulates the High-Affinity Zinc Uptake System TroCBA and the Putative Metal Chaperone YciC, along with ZinT and ZnuABC, for Survival under Zinc-Limiting Conditions

An overview ofSalmonella entericametal homeostasis pathways during infection

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