X-ray structure of the metal-sensor CnrX in both the apo- and copper-bound forms

Pompidor, Guillaume; Maillard, Antoine P.; Girard, Eric; Gambarelli, Serge; Kahn, Richard; Covès, Jacques

doi:10.1016/j.febslet.2008.10.042

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Volume 582, Issue 28 , Pages 3954-3958, 26 November 2008

X-ray structure of the metal-sensor CnrX in both the apo- and copper-bound forms

Edited by Richard Cogdell

Guillaume Pompidor
- Laboratoire des Protéines Membranaires, Institut de Biologie Structurale – Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France
Antoine P. Maillard
- Laboratoire des Protéines Membranaires, Institut de Biologie Structurale – Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France
Eric Girard
- Laboratoire des Protéines Membranaires, Institut de Biologie Structurale – Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France
Serge Gambarelli
- Laboratoire de Résonance Magnétique, Service de Chimie Inorganique et Biologique, UMR E3 CEA-UJF, Institut des Nanotechnologies et Cryogénie, CEA-Grenoble, 38054 Grenoble Cedex 9, France
Richard Kahn
- Laboratoire des Protéines Membranaires, Institut de Biologie Structurale – Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France
Jacques Covès
- Laboratoire des Protéines Membranaires, Institut de Biologie Structurale – Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France
- Corresponding author. Fax: +33 4 38 78 54 94.

Received 2 October 2008; received in revised form 17 October 2008; accepted 24 October 2008. published online 05 November 2008.

Abstract

Both the X-ray structures of the apo- and the copper-bound forms of the metal-sensor domain (residues 31–148) of CnrX from Cupriavidus metallidurans CH34 were obtained at 1.74Å resolution from a selenomethionine derivative. This four-helix hooked-hairpin is the first structure of a metal-sensor in an ECF-type signaling pathway. The copper ion is bound in a type 2-like center with a 3N1O coordination in the equatorial plane and shows an unprecedented remote fifth axial ligand with Met93 contributing a weak S–Cu bond. The signal onset cannot be explained by conformational changes associated with CnrX metallation.