Unusual Cu(I)/Ag(I) coordination of Escherichia coli CusF as revealed by atomic resolution crystallography and X-ray absorption spectroscopy

Isabell R. Loftin, Sylvia Franke, Ninian J. Blackburn, Megan M. Mcevoy

Research output: Contribution to journalArticle

92 Scopus citations


Elevated levels of copper or silver ions in the environment are an immediate threat to many organisms. Escherichia coli is able to resist the toxic effects of these ions through strictly limiting intracellular levels of Cu(I) and Ag(I). The CusCFBA system is one system in E. coli responsible for copper/silver tolerance. A key component of this system is the periplasmic copper/silver-binding protein, CusF. Here the X-ray structure and XAS data on the CusF-Ag(I) and CusF-Cu(I) complexes, respectively, are reported. In the CusF-Ag(I) structure, Ag(I) is coordinated by two methionines and a histidine, with a nearby tryptophan capping the metal site. EXAFS measurements on the CusF-Cu(I) complex show a similar environment for Cu(I). The arrangement of ligands effectively sequesters the metal from its periplasmic environment and thus may play a role in protecting the cell from the toxic ion. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish (US)
Pages (from-to)2287-2293
Number of pages7
JournalProtein Science
Issue number10
StatePublished - Oct 1 2007



  • Copper
  • Crystallography
  • Metal coordination
  • Metal tolerance
  • Silver
  • X-ray absorption spectroscopy

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology

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