Table S2. provalt html output file with details of all peptides identified for each
protein in this investigation, including number of spectra, sequences, mowse scores, % coverage, etc. Please note: Wiley-Blackwell is not responsible for the content or functionality of any supporting materials find more supplied by the authors. Any queries (other than missing material) should be directed to the corresponding author for the article. “
“Intracellular copper routing in Enterococcus hirae is accomplished by the CopZ copper chaperone. Under copper stress, CopZ donates Cu+ to the CopY repressor, thereby releasing its bound zinc and abolishing repressor–DNA interaction. This in turn induces the expression of the cop operon, which encodes CopY and CopZ, in addition to two copper ATPases, CopA and CopB. To gain further insight into the function of CopZ, the yeast two-hybrid system was used to screen for proteins interacting with the copper chaperone. This led to the identification of Gls24, a member of a family of stress response proteins. Gls24 is part of an operon containing eight genes. The operon was Sirolimus cell line induced by a range of stress conditions, but most notably by copper. Gls24 was overexpressed
and purified, and was shown by surface plasmon resonance analysis to also interact with CopZ in vitro. Circular dichroism measurements revealed that Gls24 is partially unstructured. The current findings establish a novel link between Gls24 and copper homeostasis. Copper is both an essential and a toxic trace metal in living organisms. It acts as a cofactor for >30 enzymes, such as
superoxide dismutase, cytochrome c oxidase or lysyl oxidase, but toxicity can arise when excess copper accumulates in the cell (Linder & Hazegh Azam, 1996). The two oxidation states of copper, Cu+ and Cu2+, not only allow its participation in essential redox reactions, but also to form reactive oxygen species that are known to cause cellular damage. Hence, maintenance of copper homeostasis in living organisms is critical. In the Gram-positive bacterium Enterococcus hirae, the cop operon is a key element in the maintenance of copper (-)-p-Bromotetramisole Oxalate homeostasis (Solioz & Stoyanov, 2003). The operon encodes four proteins: two copper ATPases, CopA and CopB, a copper-responsive repressor, CopY, and a copper chaperone, CopZ (Odermatt et al., 1993; Odermatt & Solioz, 1995). CopZ belongs to a family of metallochaperones that are conserved from bacteria to humans (Harrison et al., 2000). Under conditions of copper excess, CopZ donates Cu+ to the CopY repressor. This leads to the replacement of the Zn2+ cofactor of CopY by two Cu+ ions and a concomitant decrease in DNA affinity, which in turn induces the expression of the cop operon (Strausak & Solioz, 1997; Cobine et al., 2002). The transfer of copper from CopZ to CopY involves protein–protein interaction, thereby conferring specificity to the process (Cobine et al., 1999; Portmann et al., 2004).