The MerR family of transcriptional regulators

Authors

  • Nigel L Brown,

    Corresponding author
    1. School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
      *Corresponding author. Tel.: +44 (121) 414-5467; Fax: +44 (121) 414-5907, E-mail address: n.l.brown@bham.ac.uk
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  • Jivko V Stoyanov,

    1. School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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    • 1Department of Clinical Pharmacology, University of Berne, Murtenstrasse 35, CH-3010 Bern, Switzerland.

  • Stephen P Kidd,

    1. School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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    • 2

      Department of Microbiology and Parasitology, University of Queensland, Brisbane, Qld 4072, Australia.

  • Jon L Hobman

    1. School of Biosciences, The University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
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*Corresponding author. Tel.: +44 (121) 414-5467; Fax: +44 (121) 414-5907, E-mail address: n.l.brown@bham.ac.uk

Abstract

The MerR family is a group of transcriptional activators with similar N-terminal helix-turn-helix DNA binding regions and C-terminal effector binding regions that are specific to the effector recognised. The signature of the family is amino acid similarity in the first 100 amino acids, including a helix-turn-helix motif followed by a coiled-coil region. With increasing recognition of members of this class over the last decade, particularly with the advent of rapid bacterial genome sequencing, MerR-like regulators have been found in a wide range of bacterial genera, but not yet in archaea or eukaryotes. The few MerR-like regulators that have been studied experimentally have been shown to activate suboptimal σ70-dependent promoters, in which the spacing between the −35 and −10 elements recognised by the σ factor is greater than the optimal 17±1 bp. Activation of transcription is through protein-dependent DNA distortion. The majority of regulators in the family respond to environmental stimuli, such as oxidative stress, heavy metals or antibiotics. A subgroup of the family activates transcription in response to metal ions. This subgroup shows sequence similarity in the C-terminal effector binding region as well as in the N-terminal region, but it is not yet clear how metal discrimination occurs. This subgroup of MerR family regulators includes MerR itself and may have evolved to generate a variety of specific metal-responsive regulators by fine-tuning the sites of metal recognition.

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