Variation and Evolution of Metal Utilization

细胞中低水平的金属离子对于诸如氧运输、电子传递、酶活性调节或信号转导的生物功能是重要的。各种生物的进化与金属利用多样性之间的关系越来越受到人们的关注。在这项研究中，我们专注于钒结合蛋白（钒素），被认为是一个关键因素的钒积累在海鞘，海鞘。本研究的目的是探讨该蛋白是否是聚钒海鞘所特有的，聚钒蠕虫中是否存在该蛋白，如果存在同源蛋白，其功能是什么。最终目标是创建一个新的研究领域的品种和演变的金属利用1。我们通过基因组Southern印迹杂交来鉴定日本周边海域海鞘中与钒酸盐同源的基因，但未能成功。我们确定了几个钒相关蛋白的固定化金属离子亲和层析假眼溪蟹3。我们在海鞘玻璃海鞘的基因组和EST数据库中发现了五个与vanabins同源的基因。它们聚集在一个小的“基因组区域”。我们揭示了他们的能力，结合钒离子通过使用重组蛋白4。我们在另一种海鞘（Ciona savignyi）的基因组数据库中发现了6个与vanabins同源的基因。它们并不分布在基因组中三个相距遥远的区域

Metal ions at a low level in cells are important for biological functions such as oxygen transport, electron transfer, regulation of enzyme activity, or signal transduction. There is increasing interest on the relationship between evolution of various organisms and the variety of metal utilization. In this study, we focused on vanadium-binding proteins (vanabins) that are thought to be a key factor for vanadium accumulation in an ascidian, Ascidia sydneiensis samea. We intended to examine whether this protein is unique in vanadium-accumulating ascidian, whether this protein exist in vanadium-accumulating worm, what is the function of homologous proteins if exist. The final goal is to create a new research filed of variety and evolution of metal utilization1. We examined by genomic Southern blot hybridization to identify genes homologous to vanabins in ascidians collected in the sea surrounding Japan, but it failed2. We identified several vanadium-associated proteins by immobilized metal ion affinity chromatography in Pseudopotamilla occelata3. We found five genes homologues to vanabins in genome and EST databases of an ascidian, Ciona intestinalis. They are clustered in a small "genomic region. We revealed their ability to bind vanadium ions by using recombinant proteins4. We found six genes homologous to vanabins in the genome database of another ascidian, Ciona savignyi. They are not distributed in three distant regions in the genome