Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 133, Issue 12, Pages 4427-4437Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ja108890c
Keywords
-
Categories
Funding
- National Science Foundation [0449699]
- NIH [DK074192]
- Sloan Foundation
- Camille and Henry Dreyfus Foundation
- Division Of Chemistry
- Direct For Mathematical & Physical Scien [0449699] Funding Source: National Science Foundation
Ask authors/readers for more resources
Cellular acquisition of copper in eukaryotes is primarily accomplished through the Ctr family of copper transport proteins. In both humans and yeast, methionine-rich Mets motifs in the amino-terminal extracellular domain of Ctr1 are thought to be responsible for recruitment of copper at the cell surface. Unlike yeast, mammalian Ctr1 also contains extracellular histidine-rich motifs, although a role for these regions in copper uptake has not been explored in detail. Herein, synthetic model peptides containing the first 14 residues of the extracellular domain of human Ctr I (MDHSHHMGMSYMDS) have been prepared and evaluated for their apparent binding affinity to both Cu(I) and Cu(II). These studies reveal a high affinity Cu(II) binding site (log K = 11.0 +/- 0.3 at pH 7.4) at the amino-terminus of the peptide as well as a high affinity Cu(I) site (log K = 10.2 +/- 0.2 at pH 7.4) that utilizes adjacent HH residues along with an additional His or Met ligand. These model studies suggest that the histidine domains may play a direct role in copper acquisition from serum copper-binding proteins and in facilitating the reduction of Cu(II) to the active Ctr1 substrate, Cu(1). We tested this hypothesis by expressing a Ctr1 mutant lacking only extracellular histidine residues in Ctr1-knockout mouse embryonic fibroblasts. Results from live cell studies support the hypothesis that extracellular amino-terminal His residues directly participate in the copper transport function of Ctr1.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available