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Fine control of metal concentrations is necessary for cells to discern zinc from cobalt.

ABSTRACT: Bacteria possess transcription factors whose DNA-binding activity is altered upon binding to specific metals, but metal binding is not specific in vitro. Here we show that tight regulation of buffered intracellular metal concentrations is a prerequisite for metal specificity of Zur, ZntR, RcnR and FrmR in Salmonella Typhimurium. In cells, at non-inhibitory elevated concentrations, Zur and ZntR, only respond to Zn(II), RcnR to cobalt and FrmR to formaldehyde. However, in vitro all these sensors bind non-cognate metals, which alters DNA binding. We model the responses of these sensors to intracellular-buffered concentrations of Co(II) and Zn(II) based upon determined abundances, metal affinities and DNA affinities of each apo- and metalated sensor. The cognate sensors are modelled to respond at the lowest concentrations of their cognate metal, explaining specificity. However, other sensors are modelled to respond at concentrations only slightly higher, and cobalt or Zn(II) shock triggers mal-responses that match these predictions. Thus, perfect metal specificity is fine-tuned to a narrow range of buffered intracellular metal concentrations.

SUBMITTER: Osman D

PROVIDER: S-EPMC5709419 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature

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Fine control of metal concentrations is necessary for cells to discern zinc from cobalt.

Osman Deenah D Foster Andrew W AW Chen Junjun J Svedaite Kotryna K Steed Jonathan W JW Lurie-Luke Elena E Huggins Thomas G TG Robinson Nigel J NJ

Nature communications 20171201 1

Bacteria possess transcription factors whose DNA-binding activity is altered upon binding to specific metals, but metal binding is not specific in vitro. Here we show that tight regulation of buffered intracellular metal concentrations is a prerequisite for metal specificity of Zur, ZntR, RcnR and FrmR in Salmonella Typhimurium. In cells, at non-inhibitory elevated concentrations, Zur and ZntR, only respond to Zn(II), RcnR to cobalt and FrmR to formaldehyde. However, in vitro all these sensors b ...[more]

PMID: 29192165

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Fine control of metal concentrations is necessary for cells to discern zinc from cobalt.

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Fine control of metal concentrations is necessary for cells to discern zinc from cobalt.

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