RUI: Active-Site Heterogeneity in Subunits of Limulus Hemocyanin

血蓝蛋白是一种大的、含有双核铜中心的寡聚蛋白，氧是可逆结合的。双核铜中心并不是血蓝蛋白所特有的，而是存在于执行许多重要生物学功能的各种蛋白质中。然而，血蓝蛋白可以被认为是这类金属蛋白的原型。天然血蓝蛋白的大小和亚基多样性的存在阻碍了研究人员试图揭示不同物种血蓝蛋白双核铜中心的化学反应活性和光谱性质差异的结构基础。血蓝蛋白的两个亚基，命名为IIIA和IV，显示出与不同物种的血蓝蛋白之间存在的化学反应活性的差异。这些亚基的小尺寸和单双核铜中心应该会极大地促进化学、光谱和电化学研究的结构解释。我们将使用化学探针结合ESR光谱、核磁共振光谱和电化学技术来研究这两个含有完整双核铜中心的示踪亚单位和蛋白质降解片段，试图揭示不同物种血蓝蛋白双核铜中心的化学反应活性和光谱性质差异的基础。

Hemocyanins are large, oligomeric proteins containing binuclear copper centers were oxygen is reversibly bound. The binuclear copper center is not unique to hemocyanins but is present in a variety of proteins that perform many important biological functions. Hemocyanins, however, may be considered as prototypes of this general class of metalloproteins. The large size of the native hemocyanins and the existence of subunit diversity have hindered researchers in their attempts to unravel the structural basis for the disparity in chemical reactivity and spectral properties exhibited by the binuclear copper centers of hemocyanins of different species. Two subunits, designated IIIA and IV, of Limulus hemocyanin show differences in chemical reactivity similar to those that exist between the hemocyanins of different species. The small size and single binuclear copper center of these subunits should greatly facilitate the structural interpretation of chemical, spectral, and electrochemical studies. The two Limulus subunits and proteolytic fragments of these containing intact binuclear copper centers will be studied using chemical probes coupled with ESR spectroscopy, NMR spectroscopy, and electrochemical techniques in an attempt to unravel the basis of the disparity in chemical reactivity and spectral properties of the binuclear copper centers of the hemocyanins of different species.