SULFUR SPECIATION IN PLANT LEAVES/LICHENS, AND STUDIES OF METAL-CYS COMPLEXES US

植物叶子/地衣中的硫形态以及金属-CYS 复合物的研究

• 批准号: 7954197
• 负责人: FARIDEH JALILEHVAND
• 金额: $ 0.52万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-03-01 至 2010-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7954197
• 关键词: Air; Alberta province; Amino Acids; Area; Canada; Chemicals; Chemistry; Complex; Computer Retrieval of Information on Scientific Projects Database; Cysteine; Digestion; Drug Metabolic Detoxication; Electronics; Elements; Environment; Funding; Gases; Grant; Heating; Heavy Metals; Institution; Ions; Lichen - organism; Life; Ligands; Metals; Methods; Monitor; Organism; Physiological; Plant Leaves; Plants; Research; Research Personnel; Resources; Roentgen Rays; Sampling; Sampling Studies; Site; Solutions; Source; Spectrum Analysis; Structure; Sulfhydryl Compounds; Sulfur; Sulfur Metabolism Pathway; United States National Institutes of Health; X-Ray Crystallography; absorption; carboxylate; metal complex; solid state; structural biology; synchrotron radiation

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Sulfur is an essential element for plants, being converted into cysteine and then to other sulfur metabolites. Current research on sulfur metabolism in plants is severely restricted by the present "wet chemistry" methods for identifying sulfur species, which require digestion/heating/destruction of the sample and only provide rather inaccurate "total organic" vs. "total inorganic" amounts of sulfur. By means of sulfur K-edge X-ray absorption spectroscopy (XAS) we will perform detailed speciation analyses of the major sulfur species present in intact plant leaves to clarify the key steps in the sulfur metabolism. We will also study samples from areas in Alberta, Canada, exposed to well-documented extensive sour gas emissions, to investigate the effects on the sulfur metabolism. Lichens, which only take up sulfur from the air, are great natural monitors for sour gas effects. Cysteine and its derivatives are medically used for heavy metal detoxification. Cysteine, one of 21 amino acids found in living organisms, contains three coordinating sites: the amino, thiol and carboxylate groups. The thiol group can form strong bonds and accumulate ions of soft, heavy metals. Coordination chemical studies have so far been focused on metal complexes in the solid state, mostly by elemental analysis, IR and in a few cases, X-ray crystallography. Little is known about the structure and coordination in solution, near to physiological conditions. We will use metal and sulfur XAS to study the local structure around the metal center, i.e. the metal-ligand bond distances, number and type of coordinating atoms, as well as the electronic environment around the sulfur atom in complexes of heavy metals, e.g. Pb, Cd, Hg and Ag, with cysteine and its derivatives.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 硫是植物的必需元素，可转化为半胱氨酸，然后转化为其他硫代谢物。目前植物中硫代谢的研究受到目前用于识别硫物质的“湿化学”方法的严重限制，该方法需要消化/加热/破坏样品，并且只能提供相当不准确的“总有机”与“总无机”硫含量。通过硫 K 边 X 射线吸收光谱 (XAS)，我们将对完整植物叶子中存在的主要硫物种进行详细的形态分析，以阐明硫代谢的关键步骤。我们还将研究来自加拿大艾伯塔省地区的样本，这些地区暴露于有据可查的大量酸性气体排放中，以研究对硫代谢的影响。地衣只吸收空气中的硫，是酸性气体影响的天然监测器。半胱氨酸及其衍生物在医学上用于重金属解毒。半胱氨酸是生物体中发现的 21 种氨基酸之一，包含三个配位位点：氨基、硫醇基和羧酸基。硫醇基团可以形成牢固的键并积累软重金属的离子。迄今为止，配位化学研究主要集中在固态金属络合物，主要通过元素分析、红外，在少数情况下，通过 X 射线晶体学。人们对溶液中接近生理条件的结构和协调知之甚少。我们将使用金属和硫 XAS 研究金属中心周围的局部结构，即金属-配体键距、配位原子的数量和类型，以及重金属配合物中硫原子周围的电子环境，例如硫原子。 Pb、Cd、Hg 和 Ag，以及半胱氨酸及其衍生物。