Cephalopod Hemocyanins: Structure and Function

头足类血蓝蛋白：结构和功能

• 批准号: 8818697
• 负责人: Kensal Van Holde
• 金额: $ 19.37万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-02-15 至 1992-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8818697&HistoricalAwards=false
• 关键词: Cephalopod; Hemocyanins; Structure; Function

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? //

该项目的目的是了解一个非常大的多亚基蛋白的结构、组装和生理功能，即太平洋章鱼的血青素。功能大分子组合是一个非常大的多肽链的十聚体，每个质量为3.5 x 105道尔顿。每个单体链折叠成七个结构域，每个结构域携带一个氧结合位点。从c-DNA文库中提取单体链的氨基酸序列，确定整个序列。区域之间的序列比较将提供蛋白质进化的一个不同寻常的观点，因为一个原始基因的串联拷贝正在被检查。将分离具有确定目的的单个结构域（或结构域组），并尝试将氧结合功能与序列的差异联系起来，并确定不同结构域在组装过程中可能发挥的作用。如果证明有可能从一个或多个结构域被移除的亚基重新结合，将分析氧结合，以了解结合在多大程度上保留了在天然十聚体分子中观察到的合作特性。在这些观察中，一个共同的主题是整个十聚体与其部分之间氧结合的巨大差异。我们需要的是氧结合实验，使用二聚体结构或缺失一种或多种结构域类型的十聚体，来探索结构部分在整体功能中的作用。现在这可能成为可能。另一个有趣的方面是进化，软体动物和节肢动物的血青素是如何产生并独立进化的？//