Characterizing the structure of alkane hydroxylase (ALKB) and related Diiron Enzymes

表征烷烃羟化酶 (ALKB) 和相关狄铁酶的结构

基本信息

批准号：
9092672
负责人：
RACHEL Narehood AUSTIN
金额：
$ 22.15万
依托单位：
BARNARD COLLEGE
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-03-01 至 2018-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9092672
关键词：
Characterizing structure alkane hydroxylase ALKB

项目摘要

Project Summary Bacteria readily oxidize alkanes utilizing the metalloenzyme alkane hydroxylase (AlkB) and thus the actions of AlkB represent one of nature’s best defenses against the environmental effects of oil spills. Mammalian fatty acids are also desaturated by integral membrane fatty acid desaturases that are structurally quite similar to AlkB. It is not understood why AlkB catalyzes the addition of an OH group to an alkane while desaturases convert single C-C bonds to double C=C bonds. AlkB and soluble methane monooxygenase (sMMO) both catalyze the transformation of inert C-H bonds using a diiron catalyst but AlkB has a diiron catalyst with primarily nitrogen atoms as ligands while sMMO has an oxygen-rich coordination site. The coordination environment is predicted to influence the electronic structure and hence reactivity but the electronic structure of AlkB has not been characterized. The long-term objective of this research effort is to understand how the structure of AlkB determines the chemistry it affects and to use this knowledge to deepen our understanding of how biology selectively activates molecular oxygen and catalyzes the oxidation of inert hydrocarbons. An associated objective is to understand how structurally very similar biological motifs select between catalyzing the hydroxylation of alkanes or their desaturation. The primary goal of the specific research proposed is obtain a well-diffracting crystal of AlkB that will enable us to determine the three-dimensional structure of this enzyme. Related goals are to spectroscopically characterize the ground state and reactive intermediates and to begin explore AlkBs and related metalloenzymes from additional microorganisms. These goals enable us to test the hypothesis that the structures of the active sites of all AlkBs and membrane-spanning desaturases are the same but that structural differences in the substrate binding pocket control substrate selectivity and catalyst reactivity. If successful, this work would have an impact on bioinorganic chemistry and environmental chemistry. A three- dimensional structure of AlkB would help to answer many questions about the range of chemical motifs that biology can use to oxidize alkanes. It would also answer questions about some of the chemical processes utilized in the environmental response to oil spills.

项目摘要细菌易于使用金属酶烷烃羟化酶（ALKB），因此很容易氧化物烷烃，因此 ALKB代表了针对漏油的环境影响的最佳防御能力之一。哺乳动物脂肪酸还通过结构上与ALKB非常相似的整合性膜脂肪酸去饱和酶进行了去饱和。尚不理解为什么ALKB催化oh群向烷烃添加时，而去饱和酶转化单个C-C键达到双C = C键。 ALKB和固体甲烷单加氧酶（SMMO）都催化使用二铁催化剂对惰性C-H键的转化，但ALKB的二氮催化剂与一级氮原子作为配体，而SMMO具有富氧的配位位点。预测协调环境影响电子结构并因此反应性，但是ALKB的电子结构尚未特征。这项研究工作的长期目标是了解ALKB的结构确定其影响的化学反应并利用这些知识来加深我们对生物学的理解有选择地激活分子氧，并催化惰性碳氢化合物的氧化。相关的目的是了解结构上非常相似的生物学基序如何在催化催化烷烃的羟基或其去饱和度。提出的特定研究的主要目标是获得 ALKB的细分晶体晶体将使我们能够确定该酶的三维结构。相关目标是通过光谱镜来表征基态和反应性中间体，并开始从其他微生物中探索ALKB和相关的金属酶。这些目标使我们能够测试假设所有ALKB和跨膜的去饱和酶的活性位点的结构都是相同的但是，底物结合袋控制底物选择性和催化剂反应性的结构差异。如果成功，这项工作将对生物无机化学和环境化学产生影响。一个三 ALKB的尺寸结构将有助于回答有关化学图案范围的许多问题生物学可以用于氧化烷烃。这也将回答有关某些化学过程的问题用于对漏油的环境反应。