Sugar Toxicity: The Superoxide Connection

糖毒性：超氧化物的联系

基本信息

批准号：
6778139
负责人：
IRWIN FRIDOVICH
金额：
$ 19.25万
依托单位：
DUKE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-09-01 至 2006-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/6778139
关键词：
Escherichia coli carbohydrate metabolism carbon sulfur lyase gene mutation glutathione hydrogen peroxide microorganism metabolism molecular cloning nucleic acid sequence superoxide dismutase superoxides

项目摘要

Sugars in their open chain conformations are prone to enolization and subsequent autoxidation that yields 1,2 - dicarbonyls capable of covalently modifying proteins and nucleic acids. Superoxide (02 ) both initiates and propagates the oxidation of enediols. Glycation of proteins and subsequent oxidation of the resultant E-Amino fructosyl-lysine residues yields a variety of products, including 1, 2-dicarbonyls. This is believed to be responsible for the deleterious consequences of the hyperglycemia of poorly controlled diabetes mellitus. Our goals are: to further elucidate this deleterious interaction of O2 with sugars using Escherichia coli as our model. We will: isolate, sequence, and clone the defensive glyoxalase III (glo III); create mutants defective in glo III and explore their resistance to short chain sugars and to O2 ; create the glo III mutants in the sod A, sod B background, and in the gsh A background and probe how much the lack of SOD and of GSH exacerbates the glo III deficiency; and to use the superoxide dismutase mimic Mn (III) TM-2-PyP to try to alleviate the consequences of these lacks of glo III. We will explore the substrate specificity of Glo III and compare the kinetic parameters of the different substrates. We will try to find competitive inhibitors of Glo III. We will also explore the reason for the extreme sensitivity of Glo III to inactivation by O2 and by H2O2. What we ,learn with E. coli will certainly illuminate the interactions of O2 and sugars in higher organism.

开放链构象中的糖易于耐烯化和随后的自氧化，产生1,2-二甲苯甲酮，能够共价修饰蛋白质和核酸。超氧化物（02）既可以启动并传播依二醇的氧化。蛋白质的糖基化以及随后的氧化氧化，其氧化型E-氨基果糖基 - 赖氨酸残基会产生多种产物，包括1个，2-二甲苯。据信这是导致控制不良糖尿病的高血糖的有害后果。我们的目标是：进一步阐明使用大肠杆菌作为我们的模型的O2与糖的这种有害相互作用。我们将：分离，序列和克隆防御性乙二醛酶III（GLO III）；在Glo III中产生突变体，并探索它们对短链糖和O2的抗性；在SOD A，SOD B背景中创建Glo III突变体，并在GSH背景和探测中缺乏SOD和GSH的程度加剧了Glo III缺乏症；并使用超氧化物歧化酶模仿MN（III）TM-2-pyp来减轻这些缺乏GLO III的后果。我们将探索GLO III的底物特异性，并比较不同底物的动力学参数。我们将尝试找到GLO III的竞争抑制剂。我们还将探讨Glo III对O2和H2O2灭活的极端敏感性的原因。我们从大肠杆菌中学到的东西肯定会照亮高等生物体中O2和糖的相互作用。