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Nat Struct Biol. 2003 Oct;10(10):794-9. Epub 2003 Sep 14.

Crystal structure of the nickel-responsive transcription factor NikR.

Author information

1
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139 USA.

Abstract

NikR is a metal-responsive transcription factor that controls nickel uptake in Escherichia coli by regulating expression of a nickel-specific ATP-binding cassette (ABC) transporter. We have determined the first two structures of NikR: the full-length apo repressor at a resolution of 2.3 A and the nickel-bound C-terminal regulatory domain at a resolution of 1.4 A. NikR is the only known metal-responsive member of the ribbon-helix-helix family of transcription factors, and its structure has a quaternary arrangement consisting of two dimeric DNA-binding domains separated by a tetrameric regulatory domain that binds nickel. The position of the C-terminal regulatory domain enforces a large spacing between the contacts that each NikR DNA-binding domain can make with the nik operator. The regulatory domain of NikR contains four nickel-binding sites at the tetramer interface, each exhibiting a novel square-planar coordination by three histidines and one cysteine side chain.

PMID:
12970756
DOI:
10.1038/nsb985
[Indexed for MEDLINE]

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