Copper homeostasis inEnterococcus hirae

Abstract

Copper is an essential component of life because of its convenient redox potential of 200^800 mV when bound to protein. Extensive insight into copper homeostasis has only emerged in the last decade and Enterococcus hirae has served as a paradigm for many aspects of the process. The cop operon of E. hirae regulates copper uptake, availability, and export. It consists of four genes that encode a repressor, CopY, a copper chaperone, CopZ, and two CPx-type copper ATPases, CopA and CopB. Most of these components have been conserved across the three evolutionary kingdoms. The four Cop proteins have been studied in vivo as well as in vitro and their function is understood in some detail.

Mutagenesis of a Copper P-Type ATPase Encoding Genein Methylococcus capsulatus (Bath) Results inCopper-Resistance

“…hirae CopB [2], E. coli CopA, Synechococcus elongates PacS and Synechococcus sp. CtaA [20] were retrieved via the National Center for Biotechnology Information (NCBI) website (http://www.ncbi.nlm.nih.gov/).…”

“…Therefore, copper uptake and the intracellular copper quota must be precisely controlled. Many proteins are involved in coordination of copper homeostasis to be delivered to copper-containing proteins and sub-cellular compartments [2].…”

“…In both examples, it has been shown that, copA encodes for a copper-translocating P-type ATPase (CopA) which is a main component in copper homeostasis and transports copper across membranes [2], [3]. P-type ATPases are a family of membrane proteins which are ubiquitous in all life forms, and they are acting as pumps for several ions.…”

Stalking metal-linked dimers

“…One of the best understood copper homeostasis systems is that of the Gram-positive bacterium Enterococcus hirae [8][9][10][11][12][13][14][15]. The control of copper concentration in this bacterium is regulated by the cop operon, which contains the four genes copY, copZ, copA, and copB.…”

“…Pazehoski, unpublished data). In addition to the -CxCxxxxCxC-motif at the extreme C-terminus, which has been shown to bind metals and is important to the regulation of the cop operon [19,29,30], adjacent to the cysteine motif on the N-terminal side is a non-leucine zipper aliphatic repeat. We have hypothesized that both the metal binding sequence and the aliphatic repeat contribute to the formation of dimers.…”