Structure/Function of Mn and Fe Superoxide Dismutases

Mn 和 Fe 超氧化物歧化酶的结构/功能

• 批准号: 7068660
• 负责人: Thomas Christian Brunold
• 金额: $ 14.21万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-06-05 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7068660
• 关键词: active sites; atomic absorption spectrometry; biomimetics; catalyst; chemical substitution; circular dichroism; electron spin resonance spectroscopy; electronic spectra; enzyme activity; enzyme structure; iron; manganese; mathematical model; metalloenzyme; molecular dynamics; oxidative stress; protein structure function; superoxide dismutase

DESCRIPTION (provided by applicant): Superoxide dismutases (SODs) are metalloenzymes containing Mn, Fe, Cu/Zn, or Ni active sites that defend biological systems against oxidative damage mediated by the superoxide radical anion (O2), a product of aerobic metabolism. SODs have also been shown to protect against inflammation and are involved in a range of anti-cancer and anti-aging mechanisms. This proposal focuses on the structurally similar Mn- and Fe-dependent SODs, which accomplish their function through disproportionation of O2 to 02 and H202.The long-term objectives of the research outlined in this proposal are- to identify key geometric and electronic structure contributions to the reactivities of Mn- and Fe-dependent SODs and- to obtain molecular-level insight into the reaction mechanisms of these enzymes.With these goals in mind, the following specific aims have been formulated:- Generate electronic structure descriptions of the oxidized and reduced Mn- and Fe-SOD active sites.- Explore the factors responsible for SOD metal specificity.- Assess the role of second-sphere amino acids in tuning active site properties.- Define the nature of the substrate-metal interaction for Mn- and Fe-SODs and evaluate key steps in the corresponding catalytic cycles on experimental and theoretical levels.Our approach involves using a combination of spectroscopic tools (absorption, CD, MCD, EPR, and rR) and computational methods (DFT and NBO) to study the native Mn- and Fe-SOD proteins, the catalytically inactive metal-substituted Mn- and Fe-SOD species, and several mutant proteins. These studies will systematically explore geometric and electronic factors contributing to SOD activity.As SOD enzymes demonstrate therapeutic efficacy in animal models of disease states involving superoxide, low molecular weight SOD enzyme mimics (synzymes) have been proposed for the treatment of a variety of diseases. Synzymes could have distinct advantages over natural SOD enzymes as pharmaceutical agents, such as cellular permeability, lack of immunogenicity, longer lifetimes, potential for oral delivery, and lower production costs. Thus, understanding the principles by which the Mn- and Fe-SOD enzymes achieve their remarkably high catalytic rates, in particular the influence of second coordination shell amino acids on active site electronics, could aid significantly in the rational design of SOD mimics for pharmaceutical applications.

描述（由申请人提供）：超氧化物歧化酶（SOD）是含有Mn，Fe，Cu/Zn或Ni活性位点的金属酶。 SOD也已被证明可以预防炎症，并参与了一系列抗癌机制。该提案的重点是结构相似的MN和FE依赖性的草皮，通过O2至02和H202来实现其功能。该提案中概述的研究的长期目标是确定关键的几何和电子结构对Mn和Fe依赖性的Sode sodibles interiment insiment insift interifts Insights reversift interifts interifts Insperiftions的贡献，这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖于这些依赖的人。考虑到目标，已经提出了以下特定目标： - 生成对氧化和减少的Mn-和Fe-Sod活跃站点的电子结构描述。-探索负责SOD金属特异性的因素。-评估第二个球体氨基酸在调谐活性位点特性中的作用。您的方法涉及使用光谱工具（吸收，CD，MCD，EPR和RR）以及计算方法（DFT和NBO）的组合来研究天然MN-和Fe-SOD蛋白，催化催化的非活性金属含量的Mn-MN-成立Mn-和Fe-Sod-od-Sod-od-sod和Fe-sod和几种共生蛋白。这些研究将系统地探索有助于SOD活性的几何和电子因素。由于SOD酶证明了涉及超氧化物，低分子量SOD酶模仿（Synzymes）的疾病状态动物模型的治疗功效（Synzymes）。与天然SOD酶相比，Synzymes可以具有明显的优势，例如药物，例如细胞渗透性，缺乏免疫原性，更长的寿命，口服递送的潜力以及较低的生产成本。因此，了解Mn-和Fe-SOD酶达到其极高的催化速率的原理，尤其是第二配位壳氨基酸对活性位点电子产品的影响，可以在药物应用中的SOD模拟物的合理设计中显着有助于药物应用。