Recent Structural Work on the Oxygen Transport Protein Hemocyanin.
Recent Structural Work on the Oxygen Transport Protein Hemocyanin.
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氧运输蛋白血蓝蛋白的最新结构工作。
DOI：
10.1002/chin.199505320
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发表时间：
1995
期刊：
影响因子：
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通讯作者：
J. Carpenter
中科院分区：
文献类型：
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作者：
K. Magnus;H. Ton;J. Carpenter
运输氧气的能力是多细胞生物的关键生物过程。已经进化出三大类呼吸蛋白：血红蛋白、血红蛋白和血蓝蛋白。血蓝蛋白（希腊语为“蓝血”）是一种大型多亚基蛋白质，能够运输氧气，存在于各种节肢动物和软体动物中。与其他两类含铁的呼吸蛋白不同，血蓝蛋白在偶联的双核活性位点结合氧，该双核活性位点包含两个通过蛋白质侧链直接连接的铜原子。血蓝蛋白作为多亚基复合物而不是在特化细胞中在血淋巴中进行细胞外循环。一些血蓝蛋白也被证明在氧结合方面表现出高度的协同性。 1 龙虾、中断龙虾2、鲎、美洲鲎、血蓝蛋白的晶体结构取得了最新进展。 3 最近还确定了许多一级序列，这使得人们对血蓝蛋白、其结构以及其作为在调控控制下可逆地协同结合氧的分子的功能有了更深入的了解。本文将主要关注过去五年的进展，这些进展提高了我们对血蓝蛋白的一级、三级和四级结构及其协同特性的认识。节肢动物和软体动物来源的血蓝蛋白的结构之间存在重大差异。对血蓝蛋白光谱特征的广泛讨论超出了本综述的范围。简而言之，两种类型的血蓝蛋白具有相似的光谱特性，包括氧化时在约 340 和 580 nm 处的最大吸收以及相似的圆二色性和荧光光谱。此外，它们通常都不表现出电子顺磁共振，这再次表明它们的活性位点相似。电子显微镜研究表明，两种类型血蓝蛋白的四级结构非常不同，4、5，主要区别在于每种节肢动物
The ability to transport oxygen is a key biological process in multicellular organisms. Three general classes of respiratory proteins have evolved: hemoglobins, hemerythrins, and hemocyanins. The hemocyanins (Greek for “blue bloods”) are large, multisubunit proteins capable of transporting oxygen and are found in various arthropods and mollusks. Unlike the other two general classes of respiratory proteins that contain iron, hemocyanins bind oxygen at a coupled dinuclear active site containing two copper atoms directly ligated by protein side chains. Hemocyanins circulate extra-cellularly inthe hemolymph as multisubunit complexes rather than in specialized cells. Some hemocyanins have also been shown to demonstrate a high degree of cooperativity in oxygen binding. 1 Recent advances have been made in the crystal structures of the spiny lobster, Panulirus interruptus2 and horseshoe crab, Limulus polyphemus, hemocyanins. 3 Many primary sequences have also been recently determined, which has led to a greater understandingof hemocyanins, their structures, and their functions as molecules under regulatory control that bind oxygen reversibly and cooperatively. This article will concentrate primarily upon developments in the past five years that have advanced our knowledge of primary, tertiary, and quaternary structures of the hemocyaninsand their cooperative properties.Major differences exist between the architecturesof hemocyanins of arthropod and molluskan origin. Extensive discussion of spectral features of hemocyanins is outside the scope of this review. In brief, the two types of hemocyanins have similar spectral properties, including absorption maxima at about 340 and 580 nm when oxygenated and similar circular dichroic and fluorescence spectra. Also they both normally do not exhibit electron paramagnetic resonance, again sug-gesting similarity in their active sites. Electron mi-croscopic studies show that the quaternary structures of the two types of hemocyanins are quite distinct, 4, 5 with the principal difference being that each arthropod