X-Ray Absorption Spectroscopy of Metalloenzymes

金属酶的 X 射线吸收光谱

• 批准号: 7174104
• 负责人: ROBERT A SCOTT
• 金额: $ 28.55万
• 依托单位: UNIVERSITY OF GEORGIA
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 2010-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7174104
• 关键词: Active Sites; Alzheimer' s Disease; Amyloid Fibrils; Amyloid Proteins; Anabolism; Arthropods; Attention; Binding; Binding Sites; Biocompatible Materials; Biological; Cells; Chemicals; Chlamydomonas reinhardtii; Claw; Coenzymes; Collaborations; Collection; Commit; Communities; Copper; DNA Binding; Data Analyses; Data Collection; Data Set; Deposition; Development; Diet; Disease Progression; Electronics; Environment; Enzymes; Family; Family member; Funding; Generations; Halogens; Heavy Metals; Homeostasis; Human; Image; Intuition; Investigation; Jaw; Lead; Life; Ligands; Mercury; Metal Binding Site; Metalloproteins; Metals; Methodology; Methods; Micronutrients; Molecular; Molecular Structure; Nature; Numbers; Nutritional; Operon; Organism; Pattern; Peptides; Process; Proteins; Public Health; Pump; Resistance; Resolution; Roentgen Rays; Sampling; Selenium; Selenocysteine; Series; Site; Solutions; Spectrum Analysis; Sting Injury; Structural Models; Structure; Structure-Activity Relationship; Sulfur; System; Targeted Research; Techniques; Tissues; Trace Elements; Transcriptional Regulation; Transition Elements; Variant; Work; absorption; base; computational chemistry; cytochrome c oxidase; interest; lipoic acid synthase; metalloenzyme; next generation; oxidation; protein aggregation; response; selenophosphate synthetase; selenoprotein; sensor; simulation; synchrotron radiation; tool; toxic metal

DESCRIPTION (provided by applicant): This research targets structure-function relationships in selected metalloenzymes, metalloproteins, and metal-containing biomaterials, using synchrotron radiation-based X-ray absorption spectroscopy (XAS). XAS provides direct local structural information about metal and metalloid (e.g., Se, As) coordination environments and also probes the electronic structure (e.g., oxidation states) of these sites in amorphous (non-crystalline) biological systems. Specific applications include: (1) the relationship of metal coordination environment to DNA binding ability of a number of metalloregulatory and metallosensor proteins, especially those in the ArsR/SmtB and MerR families. This application seeks to understand the molecular mechanisms of organism response to metals in the cellular environment, both toxic heavy metals and essential metals. Several examples of metal sensors and metal transporters involved in metal homeostasis will be characterized. (2) the molecular mechanisms of the essential micronutrient selenium in its biological interactions. First, we will study the mechanism of selenophosphate synthetase, involved in the first committed step of selenocysteine incorporation into proteins. Second, we will use Se substitution for S as a spectroscopic probe to understand the involvement of Fe-S clusters in S-adenosylmethionine (SAM)-dependent radical generation in this enzyme super-family. (3) the molecular environment of metal-halogen biomaterials that are deposited in arthropod (and other) cuticular structures (in jaws, claws, stings, etc.). These biomaterials are non-crystalline and very hard but their detailed structure and biosynthesis is unknown. XAS microprobe methods will be used to investigate the micrometer-scale structure of these materials. Parallel to these XAS applications, a next-generation approach to EXAFS data analysis will be pursued to integrate computational chemistry as a quantitative surrogate for "chemical intuition" in interpreting EXAFS in terms of molecular structure. Public health depends on understanding the nutritional and toxicological effects of metals in the human diet and environment. The human organism must be able to maintain optimal levels of a variety of metals (as trace elements) in their proper place within tissues and cells. Understanding how both essential and toxic metals interact with biological systems will lead to nutritional and pharmacological advances.

描述（由申请人提供）：本研究的目标是使用基于同步加速器辐射的 X 射线吸收光谱 (XAS)，研究选定的金属酶、金属蛋白和含金属生物材料的结构-功能关系。 XAS 提供有关金属和准金属（例如 Se、As）配位环境的直接局部结构信息，并探测非晶（非晶体）生物系统中这些位点的电子结构（例如氧化态）。具体应用包括：（1）金属配位环境与许多金属调节和金属传感器蛋白，特别是ArsR/SmtB和MerR家族中的DNA结合能力的关系。该应用旨在了解生物体对细胞环境中的金属（有毒重金属和必需金属）反应的分子机制。将描述参与金属稳态的金属传感器和金属转运蛋白的几个例子。 (2)必需微量营养素硒在生物相互作用中的分子机制。首先，我们将研究硒磷酸合成酶的机制，该酶参与硒代半胱氨酸掺入蛋白质的第一个关键步骤。其次，我们将使用 Se 取代 S 作为光谱探针来了解 Fe-S 簇在该酶超家族中 S-腺苷甲硫氨酸 (SAM) 依赖性自由基生成中的参与。 （3）沉积在节肢动物（和其他）表皮结构（颌、爪、刺等）中的金属卤素生物材料的分子环境。这些生物材料是非晶体且非常坚硬，但其详细结构和生物合成尚不清楚。 XAS 微探针方法将用于研究这些材料的微米级结构。与这些 XAS 应用并行，我们将寻求下一代 EXAFS 数据分析方法，将计算化学整合为“化学直觉”的定量替代品，以分子结构解释 EXAFS。公共健康取决于对人类饮食和环境中金属的营养和毒理学影响的了解。人体有机体必须能够将各种金属（作为微量元素）维持在组织和细胞内适当位置的最佳水平。了解必需金属和有毒金属如何与生物系统相互作用将带来营养和药理学的进步。