BINDING OF CADMIUM AND ZINC BY A CD/ZN ATPASE INVOLVED IN METAL HYPERACCUMULATIO

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 植物对重金属的吸收是一个重要的研究领域，不仅在基础研究意义上，而且因为它对人类营养的影响以及它在污染土壤植物修复中的应用。对于后一项任务，以及从天然富含金属的土壤中商业提取金属，然而，不适合常规采矿作业，超富集植物是至关重要的。这些植物能够在其地上部分的干物质中积累百分之几的金属;这些植物的不寻常的生理学是世界范围内密集研究的主题。在这一研究领域中，目前最有趣的课题之一是将金属从根部引导到其最终储存部位的转运蛋白的生物化学和生物物理学。在当前的项目中，我们成功地从天然状态的超积累植物根中纯化了Cd/Zn ATP酶（TcHMA 4）（Parameswaran等人，2007），我们现在想进一步研究TcHMA 4中的哪些配体结合金属（在这种情况下是镉）。该蛋白属于也存在于人类中的P1 B型ATP酶，并且该泵家族的几个成员涉及由铜ATP酶突变引起的重要疾病，如门克斯病和威尔逊病。虽然基因是已知的，但对P1 B型ATP酶的生物化学和生物物理学知之甚少，因为难以实现纯化。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Heavy metal uptake in plants is an important research area not only in the sense of basic research, but also because of its impact on human nutrition and its application for the phytoremediation of contaminated soils. For the latter task, as well as for the commercial extraction of metals from naturally metal-rich soils that are, however, unsuitable for conventional mining operations, hyperaccumulator plants are of primary importance. These plants are able to accumulate several percent of metals in the dry mass of their above-ground parts; the unusual physiology of these plants is a topic of intensive worldwide research efforts. One of the presently most interesting topics in this area of research are the biochemistry and biophysics of transporters that lead metal from the roots to their final storage site in the shoot. In the current project we successfully purified a Cd/Zn ATPase (TcHMA4) from hyperaccumulator roots in its native state (Parameswaran et al., 2007) and we now want to further investigate which ligands in TcHMA4 bind metal (in this case cadmium). The protein belongs to the P1B-type ATPases that are present in humans as well and several members of this family of pumps are involved in important diseases like the Menkes and Wilsons diseases that are caused by mutation in copper ATPases. While the genes are known, only little is known about biochemistry and biophysics of P1B-type ATPases as the purification is difficult to achieve.