Institute of Analytical Chemistry, University of Copenhagen, 2100 Copenhagen, Denmark.
J Am Chem Soc. 2009 Dec 30;131(51):18226-7. doi: 10.1021/ja908793d.
Control of electron transfer rates, caused by intrinsic protein structural properties, is an intriguing feature of internal biological electron transfer (ET) reactions. The small laccase (SLAC) isolated from Streptomyces coelicolor has recently been shown to have structural and reactivity features distinct from those of other laccases. While other copper oxidases contain three cupredoxin domains, the SLAC 3D structure has recently been determined and shown to consist of only two, and a different reaction intermediate has been reported for it. It was therefore of particular interest to investigate the intramolecular ET between the type 1 and the trinuclear copper center in SLAC which is a crucial step in the catalytic cycle of the multicopper oxidases, leading to dioxygen reduction to water. This ET step was found to markedly depend on the reduction state of the enzyme, possibly reflecting site-site interactions so far not observed in other multicopper oxidases.
控制电子转移速率，这是由内在蛋白质结构特性引起的，是内部生物电子转移（ET）反应的一个有趣特征。从链霉菌中分离出的小漆酶（SLAC）最近被证明具有与其他漆酶不同的结构和反应特性。虽然其他铜氧化酶含有三个 cupredoxin 结构域，但 SLAC 的 3D 结构最近已被确定，仅由两个组成，并且报告了不同的反应中间体。因此，研究 SLAC 中 1 型和三核铜中心之间的分子内 ET 特别有趣，这是多铜氧化酶催化循环中的关键步骤，导致氧气还原为水。发现该 ET 步骤明显取决于酶的还原状态，这可能反映了迄今在其他多铜氧化酶中未观察到的位点-位点相互作用。
