Structure, Function and Transcriptional Regulation of a Copper-Specific Metallothionein in Callinectes sapidus

摘要提案MCB-0080075 PI：Marius Brouwer生物体依赖于微量金属，如铁和铜的各种功能。然而，当这些金属过量时，它们可能具有毒性作用。该研究项目的目标是进一步了解生物体将潜在的有毒铜转化为生物有用形式的分子策略，同时避免其毒副作用。许多生物使用金属特异性蛋白质，称为金属硫蛋白，用于解毒有毒金属，如镉和汞，以及解毒过量的必需金属，如铜。该项目使用蓝蟹，这种生物具有非常活跃的铜代谢，与血蓝蛋白的合成和降解相关，血蓝蛋白是一种铜依赖性蛋白质，动物使用它将氧气从鳃输送到组织。 早期的研究发现，螃蟹有金属硫蛋白，由锌控制，在脊椎动物中，但也有铜特异性金属硫蛋白，其合成由铜控制，而不是由锌。这个研究项目有三个目标。首先，将检验铜特异性金属硫蛋白可以提供血蓝蛋白生物合成所需的铜的假设。这些研究可能揭示了一个新的生物学功能的金属硫蛋白家族的新成员。其次，由于在分子水平上理解蛋白质的功能需要了解其结构，因此将确定金属硫蛋白的三维结构。这些研究将提供高等生物铜金属硫蛋白的第一个结构。第三，研究铜金属硫蛋白基因的转录调控。这项工作可能会导致在第一次演示的铜感应转录因子在高等生物体，并可能提供基础上，进一步研究铜传感和信号在高等生物体可能是基于。

ABSTRACT Proposal MCB-0080075PI: Marius BrouwerOrganisms are dependent on trace metals such as iron and copper for various functions. However, when these metals are in excess they may have toxic effects. The goal of this research project is to further our understanding of the molecular strategies used by organisms to convert potentially toxic copper into a biologically useful form, while avoiding its toxic side effects. Many organisms use metal-specific proteins, called metallothioneins, for detoxification of toxic metals, such as cadmium and mercury, and for detoxification of excess essential metals, such as copper. This project uses the blue crab, an organism that has a very active copper metabolism associated with the synthesis and degradation of hemocyanin, a copper-dependent protein used by the animal to carry oxygen from the gills to the tissues. Earlier work has found that crabs have metallothioneins that are controlled by zinc, as in vertebrates, but also have a copper-specific metallothionein whose synthesis is controlled by copper and not by zinc. This research project has three objectives. First, the hypothesis that the copper-specific metallothionein can provide copper that is required for the biosynthesis of hemocyanin will be examined. These studies may reveal a novel biological function for this new member of the metallothionein family. Secondly, since understanding of the function of a protein at the molecular level requires knowledge of its structure, the three-dimensional structure of the metallothionein protein will be determined. These studies will provide the first structure of a copper-metallothionein of a higher organism. Thirdly, the transcriptional control of the copper-metallothionein gene will be studied. This work may result in the first demonstration of a copper-sensing transcription factor in a higher organism, and may provide the foundation upon which further studies on copper sensing and signaling in higher organisms may be based.