Bioinorganic chemistry of metalloproteins and tetrapyrroles

金属蛋白和四吡咯的生物无机化学

• 批准号: RGPIN-2020-06545
• 负责人: Stillman, Martin
• 金额: $ 2.62万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=748108
• 关键词: Bioinorganic; chemistry; metalloproteins; tetrapyrroles

The foundation of our research programme is the bioinorganic chemistry of metalloproteins and synthetic analogs. Metal-containing proteins dominate Life. A wide range of essential metals fulfill roles from ionic balance, nerve, and muscle action to structural stability (often zinc) to catalytic activity (for example iron). These metals must be inserted into the apoprotein and the structural integrity of the resulting holoprotein assured for optimal, physiological activity. A key cellular aspect is the storage of metals following absorption from nutritional sources. Transition and d-block metals must be bound to chaperones to avoid unwanted and potentially toxic cellular-based reactivity. The metalation pathways, binding constants, reaction mechanisms and the structural impact of metallation on proteins are our focus. These studies are supported by expertise with a wide range of instrumental resources to probe the underlying properties of the biologically demanding molecular systems. Our research makes use of computational data to predict optical and redox properties of the metal-binding sites. Three technologies dominate our studies: (i) Quantitative analytical measurements primarily from equilibrium-, time- and temperature-dependent properties determined by electrospray-ionization mass spectrometry (ESI-MS). (ii) Detailed optical spectroscopic measurements that identify metalated speciation, ligand coordination and spin and oxidation states. (iii) Computational studies of the geometric and electronic structures of complexes involving molecular dynamics for metalloprotein structures and docking, and DFT and TD-DFT methods for coordination geometries and excited state properties. Two classes of metalloprotein and the tetrapyrroles form the core focus of our programme. (i) Proteins that are dependent on metals for activity (specifically, transferrin, heme proteins, carbonic anhydrase, and superoxide dismutase). (ii) Metallothionein, a copper and zinc cellular storage protein that subsequently transfers these metals to metalloenzymes, but in addition this protein scavenges for toxic metals, and, finally, can act as a gate-keeper for the cell, guarding against intrusion by xenobiotic metals (such as metal-containing drugs). Our proposed studies are directly applicable to the protein misfolding currently the focus in catastrophic neurological diseases. We will use computational studies of metal-binding sites to understand the specific chemistries involved during folding. (iii) Tetrapyrroles are the cofactors of heme proteins, and synthetically, as porphyrins and phthalocyanines, offer remarkably diverse properties from the chlorins in chlorophylls, to the porphyrins in the P450 cytochromes and in the oxygen processing apparatus. The synthetic chlorophyll analogs are key to devices that can act as photon collectors in solar cells. Our computationally-guided synthesis will highlight key molecular factors to enhance photosensitizer activity.

我们的研究计划的基础是金属蛋白和合成类似物的生物无机化学。含金属蛋白质主宰生命。各种必需金属发挥着从离子平衡、神经和肌肉作用到结构稳定性（通常是锌）到催化活性（例如铁）的作用。这些金属必须插入脱辅基蛋白中，并确保所得全蛋白的结构完整性以获得最佳生理活性。一个关键的细胞方面是从营养来源吸收后金属的储存。过渡金属和d区金属必须与分子伴侣结合，以避免不必要的和潜在的毒性细胞基反应。金属化途径、结合常数、反应机理以及金属化对蛋白质结构的影响是我们的重点。这些研究得到了广泛的仪器资源的专业知识的支持，以探测生物学要求高的分子系统的基本特性。我们的研究利用计算数据来预测金属结合位点的光学和氧化还原性质。 三种技术主导了我们的研究：（一）定量分析测量主要是从平衡，时间和温度依赖性的电喷雾电离质谱法（ESI-MS）确定的属性。(ii)详细的光学光谱测量，确定金属化形态，配体配位和自旋和氧化态。(iii)配合物的几何和电子结构的计算研究，涉及金属蛋白质结构和对接的分子动力学，以及配位几何和激发态性质的DFT和TD-DFT方法。两类金属蛋白和四吡咯形成了我们计划的核心焦点。 (i)依赖金属活性的蛋白质（特别是转铁蛋白、血红素蛋白、碳酸酐酶和超氧化物歧化酶）。 (ii)金属硫蛋白，一种铜和锌的细胞储存蛋白，随后将这些金属转移到金属酶，但除此之外，这种蛋白质还可以清除有毒金属，最后可以作为细胞的看门人，防止外来金属（如含金属药物）的侵入。我们提出的研究直接适用于蛋白质错误折叠目前的重点在灾难性的神经系统疾病。我们将使用金属结合位点的计算研究来了解折叠过程中涉及的特定化学反应。(iii)四吡咯是血红素蛋白的辅因子，并且作为卟啉和酞菁合成，提供从叶绿素中的二氢卟酚到P450细胞色素和氧处理装置中的卟啉的显著不同的性质。合成叶绿素类似物是可以充当太阳能电池中光子收集器的设备的关键。我们的计算指导合成将突出关键分子因素，以提高光敏剂的活性。