The PcoC copper resistance protein coordinates Cu(I) via novel S-methionine interactions

Katrina Peariso, David L. Huffman, James E. Penner-Hahn, Thomas V. O'Halloran

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The E. coli copper resistance protein PcoC enhances survival of a bacterium under conditions of extreme copper stress. This small protein has no cysteines, but does have an unusual methionine-rich sequence motif, suggesting that methionine ligation may be important in Cu binding. It is shown that PcoC binds both Cu(I) and Cu(II), in addition to binding Hg(II) and Ag(I). Previously crystallographic studies of PcoC had shown that the apo protein adopts a β-barrel fold typical of that seen for blue-copper electron-transfer proteins. However, in contrast with electron-transfer proteins, where the Cu(I) and Cu(II) structures are nearly identical, X-ray absorption spectra show that the structures of the Cu site in reduced and oxidized PcoC are dramatically different. Cu(II) PcoC has a tetragonal Cu structure in which the Cu is coordinated to O or N ligands, including at least two histidine ligands. Cu(I) PcoC has a trigonal site with two methionine ligands. This is the first well-characterized example of a methionine-rich protein Cu binding site, demonstrating a new type of biological Cu coordination chemistry.

Original languageEnglish (US)
Pages (from-to)342-343
Number of pages2
JournalJournal of the American Chemical Society
Issue number2
StatePublished - Jan 15 2003

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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