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Role of Phytochelatins on Metal Metabolism in Plants

植物螯合素对植物金属代谢的作用

基本信息

批准号：
07456038
负责人：
YOSHIMURA Etsuo
金额：
$ 4.93万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07456038/
关键词：
Phytochelatins Cadystins Cadmium Plants

项目摘要

1) PHYTOCHELATIN SYNTHESISPhytochelatin were synthesized by Fmoc method. The crude product synthesized was purified by HPLC,lyophilized and then synthetic PC-2 was obtained with the yield through the whole process of 32%. The retention time and NMR spectrum was compared to PC-2 which was induced in fission yeast, Schizosaccharomyce pombe, and purified from it and these are concluded to be identical.2) STRUCTURAL ANALYSIS of Cd-PC COMPLEXThe signals in NMR spectrum of PC-2 were assigned by 1H-1H COSY,13C-1H COSY,HMBC.It has been suggested that thiol groups in PC-2 plays an important role formation of Cd-PC complex, amid and carboxy groups contributing with smaller extent. The presence of stereoisomers and the mutural interchanges between them have been suggested. We have deduced from the electronic absorption spectra that the structures change with Cd-PC ratio. Under the conditions of lower Cd-PC ratio, a Cd atom binds two molecules of PC with tetrahedral configuration of sulfur atoms around Cd. The tetrahedral structure has been shown to be distored by donation of carboxy or amino group when Cd : PC ratio increased.3) STRUCTURAL ANALYSIS of Cd-PC COMPLEXIt has been indicated from electronic absorption spectra that a Zn atom bind to a PC molecule with a giometry of tetrahedral irespective of the Zn : PC ratio. Two thiols, and amids and/or carboxyl groups, therefore, were contribution to the formation of the complex.4) ConclusionBinding of metal ions has been clarified from dynamic aspect. However, the conplex involves acid labile sulfide in vivo, so that the analysis including the sulfide will be necessary.

1)用Fmoc法合成了植物螯合素。合成的粗品经高效液相色谱纯化、冷冻干燥后得到PC-2，全程收率为32%。2)CD-PC COMPLEX的结构分析PC-2的核磁共振谱信号由1H-1H COSY，13C-1H COSY，HMBC指认。结果表明，PC-2中的硫醇基团对CD-PC络合物的形成起重要作用，而羧基的贡献较小。已经提出了立体异构体的存在以及它们之间的相互交换。从电子吸收光谱推断，结构随Cd-Pc比例的变化而变化。在较低的Cd-Pc比条件下，一个Cd原子以Cd周围硫原子的四面体构型结合在两个Pc分子上。3)Cd-Pc络合物的结构分析从电子吸收光谱可以看出，锌原子与Pc分子的结合符合与Cd：Pc的比例成四面体几何关系。因此，两个硫醇、酰胺和/或羧基是形成络合物的原因。4)结论从动力学角度阐明了金属离子的结合。然而，该复合体中含有体内酸性不稳定的硫化物，因此包括硫化物在内的分析是必要的。