Ducros V, Brzozowski A M, Wilson K S, Brown S H, Ostergaard P, Schneider P, Yaver D S, Pedersen A H, Davies G J
Department of Chemistry, University of York, Heslington, UK.
Nat Struct Biol. 1998 Apr;5(4):310-6. doi: 10.1038/nsb0498-310.
Laccase catalyses the oxidation of a variety of organic substrates coupled to the reduction of oxygen to water. It is widely believed to be the simplest representative of the ubiquitous blue multi-copper oxidase family. Laccase is implicated in a wide spectrum of biological activities and, in particular, plays a key role in morphogenesis, development and lignin metabolism in fungi and plants. The structure of laccase from the fungus Coprinus cinereus has been determined by X-ray crystallography at a resolution of 2.2 A. Laccase is a monomer composed of three cupredoxin-like beta-sandwich domains, similar to that found in ascorbate oxidase. In contrast to ascorbate oxidase, however, the mononuclear type-1 Cu site lacks the axial methionine ligand and so exhibits trigonal planar coordination, consistent with its elevated redox potential. Crucially, the structure is trapped in a Cu depleted form in which the putative type-2 Cu atom is completely absent, but in which the remaining type-1 and type-3 Cu sites display full occupancy. Type-2 Cu depletion has unexpected consequences for the coordination of the remaining type-3 Cu atoms.
漆酶催化多种有机底物的氧化反应，并将氧气还原为水。人们普遍认为它是无处不在的蓝色多铜氧化酶家族中最简单的代表。漆酶参与了广泛的生物活性，尤其在真菌和植物的形态发生、发育及木质素代谢中发挥关键作用。通过X射线晶体学已确定了灰盖鬼伞真菌漆酶的结构，分辨率为2.2埃。漆酶是一种单体，由三个类铜蓝蛋白β-三明治结构域组成，类似于抗坏血酸氧化酶中的结构域。然而，与抗坏血酸氧化酶不同的是，单核1型铜位点缺少轴向甲硫氨酸配体，因此呈现三角平面配位，这与其较高的氧化还原电位一致。至关重要的是，该结构被困在一种铜耗尽的形式中，其中假定的2型铜原子完全缺失，但其余的1型和3型铜位点显示出完全占据。2型铜的缺失对其余3型铜原子的配位产生了意想不到的影响。
