X-ray absorption studies of yeast copper metallothionein

• Published in: The Journal of biological chemistry Vol. 263; no. 17; pp. 8199 - 8203
• Main Authors: George, G N, Byrd, J, Winge, D R
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 15.06.1988; American Society for Biochemistry and Molecular Biology
• Subjects: Algorithms; Biological and medical sciences; Carrier Proteins; Electron Probe Microanalysis; Fundamental and applied biological sciences. Psychology; Metallothionein; Molecular biophysics; Saccharomyces cerevisiae; Saccharomyces cerevisiae - analysis; Structure in molecular biology; Tridimensional structure; X-Ray Diffraction; Fungi; Yeast; Molecular structure; X ray spectrometry; Ascomycetes; Copper; Saccharomyces cerevisiae; Metallothionein; Thallophyta
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)68462-5

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.