Study of a highly selective leaching of rare metals from seawater using biological functions

钒、钴、锰、镍和钼等稀有金属在海水中的溶解度非常低。海鞘，特别是属于Phlebobranchia，已知选择性地积累高水平的钒。我们以前提取钒相关蛋白质从含钒血细胞（钒细胞）的海鞘samea。在这项研究中，全长cDNA，编码12.5 kDa和15 kDa的钒相关蛋白（命名为Vanabin），这可能有一个线索，以解决钒积累的机制，分别进行了分析。结果，Vanabin被公开为由约120个氨基酸组成，其中半胱氨酸残基的含量非常高，并且是具有α-螺旋的新型蛋白质。发现重组Vanabin与约20个钒离子原子结合，其结合常数为10 μ <-7>M。金属结合位点的研究进展最近，已经公开了12.5kDa Vanabin与+4氧化态的约10个钒原子结合，15 kDa Vanabin不与铁离子或铜离子结合，并且铜离子竞争性地抑制Vanabin与钒离子的结合。

Rare metals such as vanadium, cobalt, manganese, nickel and molybdenum are dissolved in sea water at very low levels. Ascidians, especially belonging to the Phlebobranchia, are known to selectively accumulate high levels of vanadium. We previously extracted vanadium-associated proteins from vanadium-containing blood cells (vanadocytes) of Ascidia sydneiensis samea. In this study, full-length of cDNAs, encoding 12.5 kDa and 15 kDa vanadium-associated proteins (designated newly as Vanabin), respectively, which might have a clue to resolve the mechanism of vanadium accumulation, was analyzed. As a result, Vanabin was disclosed to consist of about 120 amino acids in which the content of cysteine residues is very high and to be a novel protein having α-helix. Recombinant Vanabin was found to bind with about 20 atoms of vanadium ions and its binding constant is 10^<-7>M. Metal binding sites in progress.Recently, it has been disclosed that 12.5 kDa Vanabin binds with about 10 atoms of vanadium in the +4 oxidation state, 15 kDa Vanabin does not bind with iron ions or copper ions and copper ions inhibits the binding of Vanabin with vanadium ions, competitively.