A water-soluble supramolecular complex that mimics the heme/copper hetero-binuclear site of cytochrome c oxidase

作者：Kitagishi Hiroaki^*; Shimoji Daiki; Ohta Takehiro; Kamiya Ryo; Kudo Yasuhiro; Onoda Akira; Hayashi Takashi; Weiss Jean; Wytko Jennifer A; Kano Koji

来源：Chemical Science, 2018, 9(7): 1989-1995.

DOI：10.1039/c7sc04732k

In mitochondria, cytochrome c oxidase (CcO) catalyses the reduction of oxygen (O-2) to water by using a heme/copper hetero-binuclear active site. Here we report a highly efficient supramolecular approach for the construction of a water-soluble biomimetic model for the active site of CcO. A tridentate copper(II) complex was fixed onto 5,10,15,20-tetrakis(4-sulfonatophenyl)porphinatoiron(III) ((FeTPPS)-T-III) through supramolecular complexation between (FeTPPS)-T-III and a per-O-methylated beta-cyclodextrin dimer linked by a (2,2':6',2 ''-terpyridyl)copper(II) complex (Cu(II)TerpyCD(2)). The reduced (FeTPPS)-T-II/Cu(I)TerpyCD(2) complex reacted with O-2 in an aqueous solution at pH 7 and 25 degrees C to form a superoxo-type Fe-III-O-2 / Cu-I complex in a manner similar to CcO. The pH-dependent autoxidation of the O-2 complex suggests that water molecules gathered at the distal Cu site are possibly involved in the Fe-III-O-2(-)/Cu-I superoxo complex in an aqueous solution. Electrochemical analysis using a rotating disk electrode demonstrated the role of the FeTPPS/CuTerpyCD(2) hetero-binuclear structure in the catalytic O-2 reduction reaction.

• 出版日期2018-2-21