Characterization of a Thiolato Iron(III) Peroxy Dianion Complex
Characterization of a Thiolato Iron(III) Peroxy Dianion Complex
复制标题
DOI：
10.1002/anie.201203602
复制
发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Que, Lawrence, Jr.
中科院分区：
文献类型：
--
作者：
McDonald, Aidan R.;Van Heuvelen, Katherine M.;Que, Lawrence, Jr.
巯基与铁的连接在活性氧的酶失活中起着至关重要的作用。在微需氧菌中发现的超氧化物还原酶（SOR）催化超氧化物（O2−·）的还原，产生H2 O2 [1]，并具有一个活性位点，由一个铁中心和四个赤道His配体和一个轴向Cys配体组成。硫醇盐被认为是稳定RS-FeIII（η1-OO（−/H））中间体的O-O键，并削弱Fe-（OO）键以促进H2 O2的形成。[1，2]已经获得了O2−·和SOR之间反应中间体的证据，其在~ 600 nm处表现出可见吸收特征。[3]脉冲辐解研究表明，扩散控制的pH值无关的形成的中间体，而其衰减被发现是pH值依赖性。这些结果导致了中间体作为RS-FeII（OO·）加合物或等电子RS-FeIII（OO−）的假设;然而，其短寿命使得难以建立铁氧化
Thiolate ligation to iron plays a vital role in the enzymatic deactivation of reactive oxygen species. Superoxide reductase (SOR) found in microaerophilies catalyzes the reduction of superoxide (O2−•), yielding H2O2 [1] and has an active site that consists of an iron center with four equatorial His ligands and an axial Cys ligand. The thiolate is proposed to stabilize the O–O bond of RS-FeIII (η1-OO (−/H)) intermediates and to weaken the Fe–(OO) bond to facilitate formation of H2O2.[1, 2] Evidence for an intermediate in the reaction between O2−• and SOR has been obtained, which exhibits a visible absorption feature at~ 600 nm.[3] Pulse radiolysis studies showed diffusion-controlled pH-independent formation of the intermediate, while its decay was found to be pH-dependent. These results led to the postulation of the intermediate as either an RS-FeII (OO•) adduct or the isoelectronic RS-FeIII (OO−); however its short lifetime has made it difficult to establish the iron oxidation