Nordlund P, Eklund H
University of Stockholm, Sweden.
Curr Opin Struct Biol. 1995 Dec;5(6):758-66. doi: 10.1016/0959-440x(95)80008-5.
Di-iron centers bridged by carboxylate residues and oxide/hydroxide groups have so far been seen in four classes of proteins involved in dioxygen chemistry or phosphoryl transfer reactions. The dinuclear iron centers in these proteins are coordinated by histidines and additional carboxylate ligands. Recent structural data on some of these enzymes, combined with spectroscopic and kinetic data, can now serve as a base for detailed mechanistic suggestions. The di-iron sites in the major class of hydroxylase-oxidase enzymes, which contains ribonucleotide reductase and methane monooxygenase, show significant flexibility in the geometry of their coordination of three or more carboxylate groups. This flexibility, combined with a relatively low coordination number, and a buried environment suitable for reactive oxygen chemistry, explains their efficient harnessing of the oxidation power of molecular oxygen.
迄今为止，在参与双加氧化学反应或磷酰基转移反应的四类蛋白质中已发现由羧酸盐残基和氧化物/氢氧化物基团桥连的双铁中心。这些蛋白质中的双核铁中心由组氨酸和额外的羧酸盐配体配位。最近关于其中一些酶的结构数据，结合光谱和动力学数据，现在可以作为详细机理推测的基础。主要的羟化酶 - 氧化酶类中的双铁位点，其中包括核糖核苷酸还原酶和甲烷单加氧酶，在其与三个或更多羧酸盐基团配位的几何结构上表现出显著的灵活性。这种灵活性，再加上相对较低的配位数以及适合活性氧化学的埋藏环境，解释了它们对分子氧氧化能力的有效利用。
