Zoropogui Anthony, Gambarelli Serge, Covès Jacques
Laboratoire des Protéines Membranaires, Institut de Biologie Structurale-Jean-Pierre Ebel, UMR 5075 CNRS-CEA-UJF, 41, rue Jules Horowitz, 38027 Grenoble Cedex, France.
Biochem Biophys Res Commun. 2008 Jan 25;365(4):735-9. doi: 10.1016/j.bbrc.2007.11.030. Epub 2007 Nov 20.
CzcE is encoded by the most distal gene of the czc determinant that allows Cupriavidus metallidurans CH34 to modulate its internal concentrations of cobalt, zinc and cadmium by regulation of the expression of the efflux pump CzcCBA. We have overproduced and purified CzcE. CzcE is a periplasm-located dimeric protein able to bind specifically 4 Cu-equivalent per dimer. Spectrophotometry and EPR are indicative of type II copper with typical d-d transitions. Re-oxidation of fully reduced CzcE led to the formation of an air stable semi-reduced form binding both 2 Cu(I) and 2 Cu(II) ions. The spectroscopic characteristics of the semi-reduced form are different of those of the oxidized one, suggesting a change in the environment of Cu(II).
CzcE由czc决定簇的最远端基因编码，该基因使嗜金属贪铜菌CH34通过调节外排泵CzcCBA的表达来调节其内部钴、锌和镉的浓度。我们已经过量表达并纯化了CzcE。CzcE是一种位于周质的二聚体蛋白，每个二聚体能够特异性结合4个铜当量。分光光度法和电子顺磁共振表明其为具有典型d-d跃迁的II型铜。完全还原的CzcE的再氧化导致形成一种空气稳定的半还原形式，该形式结合2个Cu(I)离子和2个Cu(II)离子。半还原形式的光谱特征与氧化形式不同，表明Cu(II)的环境发生了变化。
