Copper chaperone cycling and degradation in the regulation of the cop operon of Enterococcus hirae.

Extensive insight into copper homeostasis has recently emerged. The Gram-positive bacterium Enterococcus hirae has been a paradigm for many aspects of the process. The cop operon of E. hirae consists of four genes that encode a repressor, CopY, a copper chaperone, CopZ, and two CPx-type copper ATPases, CopA and CopB. CopA and CopB accomplish copper uptake and export, respectively, and the expression of the cop operon is regulated by copper via the CopY repressor and the CopZ chaperone. The functions of the four Cop proteins have been extensively studied in vivo as well as in vitro and a detailed understanding of the regulation of the cop operon by copper has emerged.