Structures of the Cu(I) and Cu(II) Forms of Amine Oxidases from X-ray Absorption Spectroscopy

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• 作者：David M. Dooley ; Robert A. Scott ; Peter F. Knowles ; Christopher M. Colangelo ; Michele A. McGuirl ; and Doreen E. Brown
• 刊名：Journal of the American Chemical Society
• 出版年：1998
• 出版时间：March 25, 1998
• 年：1998
• 卷：120
• 期：11
• 页码：2599 - 2605
• 全文大小：106K
• 年卷期：v.120,no.11(March 25, 1998)
• ISSN：1520-5126

文摘

X-ray absorption spectroscopy has been used to define thecopper-site structures in both the resting(oxidized) and dithionite-reduced states of amine oxidases from bovineplasma, porcine plasma, porcine kidney,pea seedlings, and the gram-positive bacterium ArthrobacterP1. The Cu(II) EXAFS data are consistent withfour first-shell N,O scatterers (three of which are imidazoles) at adistance of 1.98-2.00 Å for all five amineoxidases. These scatterers are assigned as the equatorial ligands.Because the raw Cu(II) EXAFS data areessentially identical for all the enzymes examined, thecrystallographically defined Cu(II) sites of the peaseedling and E. coli amine oxidases are excellent models forthe copper sites in the mammalian enzymes.Analysis of the K-edges and EXAFS data for the reduced amineoxidases indicates that the Cu(I) sites arethree-coordinate, with at least two imidazoles; the range for the bonddistances among the reduced enzymesis 1.94-1.99 Å. Therefore, the results are consistent with adecrease in coordination number from five (or,possibly six) to three upon reduction of Cu(II) to Cu(I).Three-coordinate Cu(I) complexes withpredominatelyN,O ligands generally react with dioxygen, suggesting that theCu(I) sites in amine oxidases may serve thisrole in catalysis.