X-ray absorption studies of yeast copper metallothionein.
The local structures of the metal sites in copper metallothionein from Saccharomyces cerevisiae have been investigated by x-ray absorption spectroscopy at the copper and sulfur K edges. Analysis of the EXAFS (extended x-ray absorption fine structure) data indicates that each copper is trigonally coordinated to sulfur at a distance of 2.23 A. Cu-Cu interactions at 2.7 and 3.9 A have also been tentatively identified. Sulfur K edge data are compatible with cysteinyl thiolates bridging each of the eight Cu(I) ions. The data support a model for the copper cluster in yeast metallothionein consisting of a Cu8S12 core. EXAFS data on two specifically engineered carboxyl-terminal truncated mutants reveal that the copper coordination in the mutants is similar to that observed in the wild-type protein.
George
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Exxon Research & Engineering Company, Annandale, New Jersey 08801.
Byrd
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Winge
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D000465:Algorithms; D002352:Carrier Proteins; D004577:Electron Probe Microanalysis; D008668:Metallothionein; D012441:Saccharomyces cerevisiae / Q000032:analysis*; D014961:X-Ray Diffraction
C500769:CUP1-1 protein, S cerevisiae; D002352:Carrier Proteins; C007121:copper thionein; D008668:Metallothionein