A new pathway for vacuolar cadmium sequestration in Saccharomyces cerevisiae: YCF1-catalyzed transport of bis(glutathionato)cadmium
A new pathway for vacuolar cadmium sequestration in Saccharomyces cerevisiae: YCF1-catalyzed transport of bis(glutathionato)cadmium
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DOI：
10.1073/pnas.94.1.42
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发表时间：
1997-01-07
影响因子：
11.1
通讯作者：
Rea, PA
中科院分区：
文献类型：
--
作者：
Li, ZS;Lu, YP;Rea, PA
酵母镉因子（YCF 1）基因编码一个MgATP激活的谷胱甘肽S-共轭转运蛋白，负责与谷胱甘肽S-共轭后的有机化合物的液泡隔离。然而，虽然YCF 1最初是根据其赋予耐镉盐的能力分离的，但其与Cd 2+的相互作用模式以及该过程与有机谷胱甘肽缀合物转运之间的关系都是未知的。在这里，我们表明，通过直接比较从酿酒酵母菌株DTY 167，窝藏YCF 1基因的缺失，和同基因野生型菌株DTY 165，YCF 1介导的MgATP激活的液泡积累镉的液泡膜囊泡纯化。镉吸收的底物需求、动力学和Cd 2 +/谷胱甘肽化学计量以及转运活性复合物的分子量表明，YCF 1选择性地催化双（谷胱甘肽）镉（Cd .一般事务（2））。在这些结果的基础上，与DTY 165细胞相比，DTY 167细胞对Cd ~（2+）的超敏性，YCF 1介导的转运的诱导，以及Cd的快速性和自发性。GS（2）的形成--这一新的途径被认为对Cd ~（2+）的解毒有重要贡献。
The yeast cadmium factor (YCF1) gene encodes an MgATP-energized glutathione S-conjugate transporter responsible for the vacuolar sequestration of organic compounds after their S-conjugation with glutathione. However, while YCF1 was originally isolated according to its ability to confer resistance to cadmium salts, neither its mode of interaction with Cd2+ nor the relationship between this process and organic glutathione-conjugate transport are known. Here we show through direct comparisons between vacuolar membrane vesicles purified from Saccharomyces cerevisiae strain DTY167, harboring a deletion of the YCF1 gene, and the isogenic wild-type strain DTY165 that YCF1 mediates the MgATP-energized vacuolar accumulation of Cd . glutathione complexes, The substrate requirements, kinetics and Cd2+/ glutathione stoichiometry of cadmium uptake and the molecular weight of the transport-active complex demonstrate that YCF1 selectively catalyzes the transport of bis(glutathionato)cadmium (Cd . GS(2)). On the basis of these results-the Cd2+ hypersensitivity of DTY167, versus DTY165, cells, the inducibility of YCF1-mediated transport, and the rapidity and spontaneity of Cd . GS(2) formation-this new pathway is concluded to contribute substantially to Cd2+ detoxification.