Interactions of Cu(I) with Selenium-Containing Amino Acids Determined by NMR, XAS, and DFT Studies
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- 作者：Hsiao C. Wang ; Mindy Riahi ; Joshua Pothen ; Craig A. Bayse ; Pamela Riggs-Gelasco ; Julia L. Brumaghim
- 刊名：Inorganic Chemistry
- 出版年：2011
- 出版时间：November 7, 2011
- 年：2011
- 卷：50
- 期：21
- 页码：10893-10900
- 全文大小：933K
- 年卷期：v.50,no.21(November 7, 2011)
- ISSN：1520-510X
文摘
Cu(I) coordination by organoselenium compounds was recently reported as a mechanism for their prevention of copper-mediated DNA damage. To establish whether direct Se鈥揅u coordination may be involved in selenium antioxidant activity, Cu(I) coordination of the selenoamino acids methyl-Se-cysteine (MeSeCys) and selenomethionine (SeMet) was investigated. NMR results in D2O indicate that Cu(I) binds to the Se atom of both MeSeCys and SeMet as well as the carboxylic acid oxygen atom(s) or amine nitrogen atoms. X-ray absorption spectroscopy (XAS) and density functional theory (DFT) results confirm Se鈥揅u coordination, with the identification of a 2.4 脜 Se鈥揅u vector in both the Se- and Cu-EXAFS data. XAS studies also show Cu(I) in an unusual three-coordinate environment with the additional two ligands arising from O/N (2.0 脜). DFT models of 1:1 Cu-selenoamino acid complexes suggest that both selenoamino acids coordinate Cu(I) through the selenium and amino groups, with the third ligand assumed to be water. These compounds represent the first structurally characterized copper(I) complexes with sulfur- or selenium-containing amino acids.