A redox switch in CopC: An intriguing copper trafficking protein that binds copper(I) and copper(II) at different sites

A copper(I) protein possibly involved in the assembly of Cu A center of bacterial cytochrome c oxidase

“…The 2.30-Å bond distance is larger than the usual 2.24-2.26 Å Cu-S distance observed in three-coordinated Cu(I) complexes (34,35) and is consistent with a four-coordinated Cu(I) center. The x-ray absorption spectroscopy and EXAFS spectra are same as those observed in CopC, which presents the same set of copper ligands (33). The converging evidence consists of the following: (i) the large improvement of the fit quality upon adding the Cu-Ncontribution; (ii) the multiple scattering contributions of the imidazole ring to the spectrum; and (iii) the edge and near-edge features allow us to confidently identify a Cu(I)-S 3 -N(His) metal site in the DR1885 protein.…”

“…A lower match was found with copper proteins (Z-score of 2.3) such as blue oxidases (PDB ID codes 1KV7 and 1AOZ) and a bacterial periplasmic copper trafficking protein CopC (PDB ID codes 1M42, rmsd on C ␣ atoms of 3.1 Å with Cu(I)DR1885, and 1LYQ), all possessing a cupredoxin-like fold. CopC is able to bind both Cu(I) and Cu(II) in two different sites (33). None of the above-mentioned copper proteins shares high sequence similarity with DR1885 protein.…”

“…Fig. 9, which is published as supporting information on the PNAS web site, shows the edge region of the Cu(I)DR1885 sample compared with other Cu(I) binding proteins like Pseudomonas syringae CopC (33) and Sinorhizobium meliloti Cox11 (9) (see Fig. 9A), as well as the EXAFS (Fig.…”

Biological inorganic chemistry at the beginning of the 21st century

“…My second favorite metal, which took a back seat at the UBC meeting, is clearly on the move (88)(89)(90)(91)(92)(93)(94), as discussed by Bertini and A. Rosato (95). It is featured in several papers in this issue, including one by Bertini and Lucia Banci on a copper protein, CopC, which along with a multicopper oxidase, CopA, may be responsible for copper resistance in Gramnegative bacteria (96). Copper also is involved in aerobic oxidation of methane to methanol by certain bacteria.…”

Tracking metal ions through a Cu/Ag efflux pump assigns the functional roles of the periplasmic proteins

“…The preference of Cu(I) for soft bases (His, Cys, and Met) is manifest in the coordination environments of cytoplasmic metallochaperones (35)(36)(37) and the Met-rich sites found in periplasmic copperbinding proteins (38)(39)(40)(41). However, in the context of Cu(I) transport through membrane channels, kinetic lability may be more important than thermodynamic stability, and indeed high binding affinity is likely to inhibit transport, unless accompanied by energy input that can toggle high-and low-affinity states via conformational change, as has been proposed as a mechanism for intramembrane transport in P1B-type ATPases (42).…”