双核铜配合物催化的几何依赖性磷酸二酯水解反应

Geometry-dependent phosphodiester hydrolysis catalyzed by binuclear copper complexes.

作者信息

Zhu Lei, dos Santos Osvaldo, Koo Chi Wan, Rybstein Marc, Pape Louise, Canary James W

机构信息

Department of Chemistry, New York University, New York, New York 10003, USA.

出版信息

Inorg Chem. 2003 Dec 1;42(24):7912-20. doi: 10.1021/ic0340985.

DOI:10.1021/ic0340985

PMID:14632508

Abstract

Two isomeric binuclear ligands PBTPA and MBTPA and their copper(II) complexes were prepared and examined for hydrolysis of a model phosphodiester substrate: bis(p-nitrophenyl)phosphate. A bell-shaped pH vs rate profile, which is in agreement with one mechanism proposed for bimetallonucleases/phosphatases, was observed for the binuclear complex of copper(II) and PBTPA. At pH 8.4, a maximum rate of 1.14 x 10(-6) s(-1)--more than 10(4)-fold over uncatalyzed reactions--was achieved. However, the analogous complex of MBTPA did not show significant rate enhancement. The binuclear complex of copper(II) and PBTPA also showed 10-fold acceleration over mononuclear complex of copper(II) and tris(2-pyridylmethyl)amine (TPA) catalyzed reaction. A phage phiX174 DNA assay showed that the complex of copper(II) and PBTPA promoted supercoiled phage phiX174 DNA relaxation under both aerobic and anaerobic conditions, in contrast to the hydrolytic inactivity of the mononuclear complex of copper(II) and TPA.

摘要

制备了两种异构双核配体PBTPA和MBTPA及其铜（II）配合物，并对一种模型磷酸二酯底物：双（对硝基苯基）磷酸酯的水解进行了研究。对于铜（II）与PBTPA的双核配合物，观察到了钟形的pH与速率曲线，这与为双金属核酸酶/磷酸酶提出的一种机制相符。在pH 8.4时，达到了1.14×10⁻⁶ s⁻¹的最大速率——比未催化反应快10⁴倍以上。然而，MBTPA的类似配合物并未显示出显著的速率增强。铜（II）与PBTPA的双核配合物在催化反应中也比铜（II）与三（2 - 吡啶甲基）胺（TPA）的单核配合物快10倍。噬菌体φX174 DNA分析表明，与铜（II）和TPA的单核配合物的水解无活性相反，铜（II）与PBTPA的配合物在有氧和无氧条件下均能促进超螺旋噬菌体φX174 DNA的松弛。