Roosens Nancy H, Bernard Catherine, Leplae Raphael, Verbruggen Nathalie
Laboratoire de Physiologie et Génétique Moléculaire des Plantes, Université Libre de Bruxelles, Campus Plaine (CP 242) Bld du triomphe, B-1050 Brussels, Belgium.
FEBS Lett. 2004 Nov 5;577(1-2):9-16. doi: 10.1016/j.febslet.2004.08.084.
Metallothioneins chelate metals and consequently may be a control point of metal homeostasis. Homologous to type 3 metallothioneins, TcMT3 cDNA was identified in the Cd/Zn hyperaccumulator, Thlaspi caerulescens. TcMT3 amino acid sequence showed modifications in the Cys positions when compared with its Arabidopsis orthologue. A structural model established that the MT3 carboxyterminal domain is similar to the beta domain of animal metallothioneins and predicts a smaller cavity to chelate metals for A. thaliana than for T. caerulescens. Functional testing in yeast and Northern blot analysis added further evidence for adaptative variations of MT3 for the maintenance of Cu homeostasis in a metal hyperaccumulator.
金属硫蛋白能螯合金属，因此可能是金属稳态的控制点。与3型金属硫蛋白同源，在镉/锌超积累植物天蓝遏蓝菜中鉴定出了TcMT3 cDNA。与拟南芥的直系同源物相比，TcMT3氨基酸序列在半胱氨酸位置上有修饰。一个结构模型表明，MT3的羧基末端结构域与动物金属硫蛋白的β结构域相似，并预测拟南芥螯合金属的腔比天蓝遏蓝菜的小。在酵母中的功能测试和Northern印迹分析为MT3在金属超积累植物中维持铜稳态的适应性变化提供了进一步的证据。
