植物金属硫蛋白及其重金属解毒机制研究进展

Advances in Plant Metallothionein and Its Heavy Metal Detoxification Mechanisms

金属硫蛋白是一类分子量较小、富含Cys的金属结合蛋白,广泛分布于生物界。近年来从植物中克隆到许多编码金属硫蛋白的基因,并在研究基因表达模式、组织表达特异性以及基因结构,如启动子、内含子在染色体上的定位等方面取得了一定进展,但对其功能的研究还处于起步阶段。很多实验表明,植物金属硫蛋白可以通过其大量的Cys残基螯合重金属并清除活性氧,使植物免受氧化损伤。文章介绍了植物金属硫蛋白的分类、特征、基因结构及其在植物重金属解毒中的作用。

Metallothioneins, which widely distribute in eukaryotic and prokaryotic organisms, are a class of cystein-rich and heavy metal-binding proteins with low molecular weights. Many genes encoding plant metallothioneins have been cloned in the past years. There is certain progress on the expression patterns, tissue specificities and structures of these genes such as the loci of promoters and introns in chromosomes, however, their exact functions remain unknown. The expressions of many plant metallothionein genes under environmental stresses suggested that they may function in both metal chaperoning and scavenging of reactive oxygen species with their large number of cysteine residues to protect plants from oxidative damage. The classification, characteristics, gene structure of plant metallothioneins, and recent advances in heavy metal detoxification are summarized in detail.