Cephalopod Hemocyanins: Structure and Function

该项目的目的是了解一种非常大的多亚单位蛋白质--太平洋章鱼的血蓝蛋白的结构、组装和生理功能。功能性大分子组合是由非常大的多肽链组成的十聚体，每个多肽链的质量为3.5×105道尔顿。每个单体链被折叠成七个结构域，每个结构域都带有一个氧结合位点。单体链的氨基酸序列来自c-DNA文库，正在确定整个序列。结构域之间的序列比较将提供蛋白质进化的不同寻常的观点，因为正在检查原始基因的串联副本。将分离意图确定的单个结构域(或结构域组)，并尝试将氧结合功能的差异与序列相关联，并确定不同结构域在组装过程中可能发挥的作用。如果证明有可能重新结合其中一个或多个结构域已被移除的亚基，将分析氧结合，以查看结合在多大程度上保留了在天然十聚体分子中观察到的协同特性。一个共同的主题是，这些观察中的许多都是整个十角机和它的部件之间氧结合的巨大分歧。需要的是使用二聚体结构或缺失一个或多个结构域类型的十聚体进行氧结合实验，以探索部分结构在整体功能中的作用。现在，这或许是可能的。另一个有趣的方面是进化，软体动物和节肢动物血蓝蛋白是如何产生并独立进化的？

The aim of the project to understand the structure, assembly, and physiological function of a very large multi-subunit protein, the hemocyanin of the Pacific octopus, Octopus dofleini. The functional macromolecular assemblage is a decamer of very large polypeptide chains, each of mass 3.5 x 105 daltons. Each monomer chain is folded into seven domains, each of which carries an oxygen binding site. The amino acid sequence of the monomer chain from a c-DNA library, is being determined the entire sequence. Comparison of sequences between domains will provide an unusual view of protein evolution, since tandem copies of a primitive gene are being examined. Individual domains with the intention of determining (or groups of domains) will be isolated and attempts will be made to correlate differences in oxygen binding function with sequences, and to determine what role different domains may play in the assembly process. If it proves possible to reassociate subunits from which one or more domains have been removed, the oxygen binding will be analyzed to see what extent the binding retains to cooperative character observed in the native decameric molecule. A common theme is many of these observations is the great disparty in oxygen binding between the whole decamer and its parts. What is needed are oxygen binding experiments using either dimeric structure or decamers in which one or more domain types are missing, to probe the role of parts of the structure in the functioning of the whole. It may now be possible. Another aspect of interest is evolution, how did molluscan and arthropod hemocyanins arise and independently evolve? //