Role for zinc(II) in the copper(I) regulated protein CopY

Despite the importance of copper-thiolate clusters in the regulation of copper metabolism the formation chemistry of these clusters in proteins is not well understood. The number of COD ions that can be incorporated within a given molecule and their coordination number varies. CopY is a repressor protein from Enterococcus hirae which utilises a copper-thiolate cluster in the regulation of the copper homeostasis genes. Physical. biological assays of purified native reconstituted apoCopY suggest that the formation of a Zn(II)-protein prior to Cu(I) incorporation is necessary to achieve the native Cu(I)-S cluster. In this protein the Zn(II) is readily displaced by the Cu(I). CopY proteins with homologous metal binding motifs are being used to investigate cluster formation stabilisation. (C) 2002 Elsevier Science B.V. All rights reserved.