2cad

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spinqualitylabelsall models 2cad, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

NIKR FROM HELICOBACTER PYLORI IN CLOSED TRANS-CONFORMATION AND NICKEL BOUND TO 2F, 2X AND 2I SITES.

Overview

The survival of Helicobacter pylori in the human stomach critically relies, on the availability and use of nickel, an absolute cofactor of the, important virulence determinant urease. Nickel-responsive gene regulation, is mediated by HpNikR, a protein belonging to the ribbon-helix-helix, family of transcriptional regulators. Unlike its homologues, HpNikR acts, as both a repressor and an activator within an acid adaptation cascade. We, report the crystal structure of the full-length HpNikR in a nickel-free, conformation and two nickel-bound structures obtained in different, conditions: Ni1-HpNikR and Ni2-HpNikR. Apo-HpNikR shows the same global, fold as its bacterial homologues although with an unusual closed, trans-conformation and asymmetrical quaternary arrangement. The structure, of Ni1-HpNikR in the presence of nickel has two different sides, one, showing nickel binding similar to that of known NikRs and the other, reflecting an intermediate state. The structure of Ni2-HpNikR obtained, using a shorter exposure to nickel provides another snapshot of the nickel, incorporation. Altogether, the three structures have allowed us to, determine the route for nickel within HpNikR and reveal the cooperativity, between the tetramerization domain and the DNA-binding domain. Experiments, using point mutations of HpnikR residues involved in nickel, internalisation confirm that these residues are critical for HpNikR, functions in vivo.

About this Structure

2CAD is a Single protein structure of sequence from Helicobacter pylori with , , and as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.

Reference

Structural basis of the nickel response in Helicobacter pylori: crystal structures of HpNikR in Apo and nickel-bound states., Dian C, Schauer K, Kapp U, McSweeney SM, Labigne A, Terradot L, J Mol Biol. 2006 Aug 25;361(4):715-30. Epub 2006 Jul 7. PMID:16872629

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