Fraterrigo T L, Miller C, Reinhammar B, McMillin D R
Department of Chemistry, Purdue University, West Lafayette, IN 47907-1393, USA.
J Biol Inorg Chem. 1999 Apr;4(2):183-7. doi: 10.1007/s007750050303.
Understanding the structure and function of the three copper atoms in the dioxygen reduction site of the blue oxidases such as laccase has been a long standing challenge. In the case of a widely studied derivative, known as type 2-depleted laccase, the removal of one copper from the cluster abolishes the EPR signal of the so-called type 2 copper. However, the present studies of isotopically enriched protein from Polyporus versicolor show that the readily replaceable copper is not active in the low-temperature EPR spectrum of fungal laccase or its difluoride adduct. The same is true for the difluoride adduct of the tree enzyme. Thus, in type 2-depleted laccase the pattern of antiferromagnetic coupling is quite different from that of the native protein or the difluoride adduct.
了解漆酶等蓝色氧化酶的双氧还原位点中三个铜原子的结构和功能一直是一项长期挑战。在一种被广泛研究的衍生物——即2型缺失漆酶的情况下，从簇中去除一个铜会消除所谓2型铜的电子顺磁共振（EPR）信号。然而，目前对云芝同位素富集蛋白的研究表明，易于替换的铜在真菌漆酶或其二氟化物加合物的低温EPR光谱中并不活跃。树状酶的二氟化物加合物也是如此。因此，在2型缺失漆酶中，反铁磁耦合模式与天然蛋白或二氟化物加合物的模式有很大不同。
