Using XAS and SXRF to study copper in wilson disease at the molecular and tissue level

Research output: Chapter in Book/Report/Conference proceedingConference contribution

6 Scopus citations

Abstract

Wilson disease (WD) is a genetic disorder of copper metabolism associated with severe hepatic, neurological, and psychiatric abnormalities. In WD, the billiary copper excretion is impaired and copper accumulates in tissues, particularly in the liver and the brain. The affected gene, ATP7B, encodes the copper transporting ATPase, Wilson disease protein (WNDP). WNDP has six copper binding sites in the N-terminal portion of the molecule. Each site includes the conserved amino acid sequence MXCXXC, and binds 1 Cu(I) through its 2 cysteine residues. We performed X-ray absorption studies at the Cu Kα-edge on the recombinant N-terminal domain of WNDP (N-WNDP). Copper was bound to N-WNDP either in vivo or in vitro in the presence of different reducing agents. We found that in N-WNDP copper is predominantly coordinated in a linear fashion by two cysteines, with the appearance of a Cu-Cu interaction when all metal binding sites are filled. Increasing amounts of reducing agents containing sulfide or phosphine groups led to binding of the exogenous ligands to copper thereby increasing the coordination number of copper from two to three. To better understand the role of copper in WD, we utilized livers of the 6-weeks-old Atp7b-/- mice (an animal model for WD) in which the copper concentration was 10-20-fold higher compared to that of the control mice. The distribution of copper in hepatocytes was evaluated by synchrotron based X-ray fluorescence microprobe (SXRF). We demonstrate that we can prepare liver slices that retain copper and can detect copper with subcellular resolution. On the same sections μ-XANES (spot size: 5 micron) was used to determine the oxidation state of copper.

Original languageEnglish (US)
Title of host publicationX-RAY ABSORPTION FINE STRUCTURE - XAFS13
Subtitle of host publication13th International Conference
Pages328-330
Number of pages3
DOIs
StatePublished - Mar 26 2007
EventX-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference - Stanford, CA, United States
Duration: Jul 9 2006Jul 14 2006

Publication series

NameAIP Conference Proceedings
Volume882
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Other

OtherX-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference
CountryUnited States
CityStanford, CA
Period7/9/067/14/06

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Keywords

  • Copper
  • EXAFS
  • SXRF
  • Wilson disease

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Ralle, M., Blackburn, N. J., & Lutsenko, S. (2007). Using XAS and SXRF to study copper in wilson disease at the molecular and tissue level. In X-RAY ABSORPTION FINE STRUCTURE - XAFS13: 13th International Conference (pp. 328-330). (AIP Conference Proceedings; Vol. 882). https://doi.org/10.1063/1.2644515