Department of Material Sciences, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-chou, Nagoya, 466-8555, Japan.
J Biol Inorg Chem. 2012 Oct;17(7):1025-31. doi: 10.1007/s00775-012-0916-x. Epub 2012 Jul 3.
The axial interactions of Cu(2+) in type 1 copper proteins control the physical characteristics of the proteins. We tuned the geometries of a de novo designed blue copper protein with a four-helical bundle structure. The designed protein axially bound various ligands, such as chloride, phosphate, sulfate, acetate, azide, and imidazole, to Cu(2+), exhibiting a blue or green color. The UV-vis spectral bands were observed at approximately 600 nm and approximately 450 nm, with the A (450)/A (600) ratios between 0.14 and 1.58. The stronger axial interaction shifted the geometry of the type 1 copper site from trigonal planar geometry (blue copper) toward a tetrahedral-like geometry (green copper). Resonance Raman spectral analyses showed that the phosphate-bound type had the highest-strength Cu-S bond, similar to that of plastocyanin. The chloride-bound type exhibited features similar to those of stellacyanin and nitrite reductase, and the imidazole-bound type exhibited features similar to those of azurin M121E mutant.
在 1 型铜蛋白中，Cu(2+)的轴向相互作用控制着蛋白质的物理特性。我们对具有四螺旋束结构的新型设计的蓝色铜蛋白的几何形状进行了调整。设计的蛋白质轴向结合了各种配体，如氯离子、磷酸盐、硫酸盐、醋酸盐、叠氮化物和咪唑，与 Cu(2+)结合，呈现蓝色或绿色。在大约 600nm 和大约 450nm 处观察到了紫外可见光谱带，A（450）/A（600）比值在 0.14 到 1.58 之间。较强的轴向相互作用将 1 型铜位的几何形状从平面三角几何（蓝色铜）向四面体类似的几何（绿色铜）转变。共振拉曼光谱分析表明，与植物细胞色素 c 类似，磷酸盐结合的类型具有最强的 Cu-S 键。与天青蛋白和亚硝酸盐还原酶类似，氯离子结合的类型表现出与星型蛋白和亚硝酸还原酶类似的特征，而咪唑结合的类型则表现出与 M121E 突变型天青蛋白类似的特征。
