Tepper Armand W J W, Milikisyants Sergey, Sottini Silvia, Vijgenboom Erik, Groenen Edgar J J, Canters Gerard W
Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands.
J Am Chem Soc. 2009 Aug 26;131(33):11680-2. doi: 10.1021/ja900751c.
The enzyme mechanism of the Cu-containing small laccase (SLAC) from Streptomyces coelicolor has been investigated by optical and electron paramagnetic resonance spectroscopy. A new intermediate was identified after the reaction of molecular oxygen with the reduced trinuclear site of the type-1-depleted (T1D) form of the enzyme. It has the fingerprint of a biradical with a triplet ground state. One of the spins resides on a Cu in the trinuclear site, tentatively identified as the type-2 site, while the other spin derives from a protein-based radical. The latter is tentatively identified as a tyrosyl radical on the basis of the similarity of the optical characteristics with those observed for a Cu tyrosyl radical pair. The spin-spin distance was found to be 5.0 +/- 0.2 A.
通过光学和电子顺磁共振光谱研究了天蓝色链霉菌含铜小漆酶（SLAC）的酶作用机制。在分子氧与该酶1型缺失（T1D）形式的还原三核位点反应后，鉴定出一种新的中间体。它具有三重态基态双自由基的特征指纹。其中一个自旋位于三核位点的一个铜原子上，初步鉴定为2型位点，而另一个自旋来自基于蛋白质的自由基。基于光学特性与铜酪氨酸自由基对所观察到的相似性，后者初步鉴定为酪氨酸自由基。发现自旋-自旋距离为5.0±0.2埃。
