Distinct metal binding configurations in ACE1

The ACE 1 protein of Saccharomyces cerevisiae mediates the metal-induced expression of the CUP metallothionein (MT) genes. Curiously, ACE1 resembles the MT protein in the types of metal complexes that form. ACE1 binds Cd(II) and Cu(I) ions in distinct configurations, but only the Cu(I) conformer of...

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Published inBiochemistry (Easton) Vol. 32; no. 28; pp. 7294 - 7301
Main Authors Dameron, C. T, George, G. N, Arnold, P, Santhanagopalan, V, Winge, D. R
Format Journal Article
LanguageEnglish
Published Washington, DC American Chemical Society 20.07.1993
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Summary:The ACE 1 protein of Saccharomyces cerevisiae mediates the metal-induced expression of the CUP metallothionein (MT) genes. Curiously, ACE1 resembles the MT protein in the types of metal complexes that form. ACE1 binds Cd(II) and Cu(I) ions in distinct configurations, but only the Cu(I) conformer of ACE1 forms a high-affinity and specific complex with DNA. Cu(I) ions associated with ACE1 are known to assemble in a polymetallic Cu(I)-thiolate cluster that resembles Cu-metallothionein in metal coordination properties [Dameron, C. T., Winge, D. R., George, G. N., Sansone, M., Hu, S., and Hamer, D. (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 6127-6131]. In contrast to the Cu(I) nuclearity of 6-7 mol equiv in ACE1 and 7 mol equiv in yeast MT, divalent ions, including Cd(II), Zn(II), and Co(II), bind with a maximal stoichiometry of near 4 mol equiv in ACE1 and 4 mol equiv in yeast MT. Charge transfer bands consistent with metal:thiolate coordination were observed in CdACE1 and CoACE1. Spectroscopic studies of Co(II)ACE1 and EXAFS analysis of CD(II)ACE1 revealed tetrahedral coordination geometry in these complexes. Similar tetrahedral coordination complexes were observed with Co(II) and Cd(II) complexes of MT from S. cerevisiae. Metal binding in ACE1 is clearly similar to that in MT, and therefore the MT-metal clusters appear to be a good structural model of the metal center of ACE1
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ISSN:0006-2960
1520-4995
DOI:10.1021/bi00079a028