Cephalopod Hemocyanins: Structure and Function

这项研究的重点是血青素的结构和生理功能，血青素是在一些无脊椎动物的血液中发现的携带氧气的蛋白质。最近，研究人员和她的合作者确定了其中一个大分子（来自章鱼的分子）的氨基酸序列和部分三维结构。这项新提出的工作将首先检查章鱼血青素基因的一部分结构，然后尝试开发一种系统，在细菌或其他细胞中表达该基因的一部分。这最终将允许定向突变，以分析特定氨基酸对氧结合功能的影响。这种蛋白质还含有附加的碳水化合物基团；将确定代表性分子的组成和结构，并研究它们在确定蛋白质结构和/或功能方面的可能作用。最后，该项目将重点关注这些大分子的各个部分如何相互沟通，以调节许多位点上氧的合作结合。这种变构调节现象在许多其他重要蛋白质中也很常见，但仍未被完全理解。血青素是一种氧转运蛋白，只存在于软体动物和节肢动物中。章鱼的血青素确实是巨大的分子，分子量高达数百万。由于最近在这些分子的结构和序列分析方面取得了突破，研究人员准备在前所未有的复杂水平上解释血青素的进化和功能。

The study focuses on the structure and physiological function of hemocyanins, which are oxygen-carrying proteins found in the blood of some invertebrates. The amino acid sequence, and part of the 3-dimensional structure of one of these giant molecules (that from Octopus) has recently been determined by the investigator and her collaborators. The new work proposed will first examine the structure of a part of the gene for the Octopus hemocyanin, and then attempt to develop a system to express a portion of this gene in bacteria or other cells. This should ultimately allow directed mutation, to analyze the effects of particular amino acids on the oxygen binding function. The protein also contains attached carbohydrate groups; the composition and structure of representative ones will be determined, and their possible roles in determining protein structure and/or function examined. Finally, the program will focus on how portions of these giant molecules communicate with one another to regulate the cooperative binding of oxygen on many sites. This phenomenon of allosteric regulation is common to many other important proteins, and is still not completely understood.Hemocyanins are oxygen transport proteins found exclusively in molluscs and arthropods. The octopus hemocyanins are truly enormous molecules, with molecular weights in the millions. As a result of recent breakthroughs in structure and sequence analysis of these molecules, the investigators are poised to interpret the evolution and function of hemocyanin at a level of sophistication never before possible.