Butane metabolism in Pseudomonas butanovora

描述(申请人提供)：气态和液态烷烃可用作细菌生长底物。烷烃单加氧酶通过催化烷烃氧化成醇来启动烷烃的代谢。虽然甲烷和液态烷烃(如辛烷)的代谢已得到很好的研究，但对短链气态烷烃的氧化却知之甚少。申请人的研究重点是BMO作为这一未得到充分研究的烷烃利用群体的代表，以及丁烷代谢的完整途径。之前对三个利用丁烷的细菌的结果表明，在收获丁烷的酶和参与酒精后续新陈代谢的酶之间，存在着令人惊讶的多样性。研究人员现在建议只关注其中一种细菌--布坦诺拉假单胞菌。该项目的具体目标是：1.表征含有BMO的二铁，它类似于可溶性MMO，但不氧化甲烷。2.申请人发现了两个基因簇，每个基因编码一个丁醇脱氢酶和一个假定的丁醛脱氢酶，它们使用平行的电子传递途径。申请人现在提议确定这些平行路径的组成部分。3.以前的研究表明，BMO、丁醇脱氢酶和丁醛脱氢酶的产生独立地由丁烷和途径中的中间体调节。研究人员将研究调控丁烷途径在P.butanovora中诱导的分子基础。拟议的实验可能为氧化非极性分子的广泛类别的双铁单加氧酶的底物专一性基础提供独特的见解。对平行途径的研究将与其他代谢途径相关，在这些途径中，有毒代谢物必然作为支持生长的底物代谢的一部分而产生。

DESCRIPTION (provided by applicant): Gaseous and liquid alkanes can serve as bacterial growth substrates. Alkane monooxygenases initiate the metabolism of alkanes by catalyzing the oxidation of the alkanes to alcohols. While metabolism of methane and liquid alkanes (e.g., octane) is well studied, much less is known about the oxidation of short-chain, gaseous alkanes. The applicant's research has focused on BMOs as representatives of this understudied group of alkane utilizers and on the complete pathway of butane metabolism. Previous results with three butane-utilizing bacteria indicated a surprising level of diversity among the enzymes that harvest butane as well as those involved in the subsequent metabolism of the alcohols. The investigators now propose to focus on just one of these bacteria, Pseudomonas butanovora. The specific aims of the project are: 1. Characterize the diiron containing BMO, which is similar to soluble MMO, but does not oxidize methane. 2. The applicants discovered two clusters of genes, each coding for a butanol dehydrogenase and a putative butyraldehyde dehydrogenase, which use parallel pathways of electron transport. The applicant now proposes to identify the components of these parallel pathways. 3. Previous studies indicated independent regulation of the production of BMO, butanol dehydrogenases and butyraldehyde dehydrogenases by butane and intermediates in the pathway. The investigators will examine the molecular basis of the regulation of induction of the butane pathway in P. butanovora. The proposed experiments may provide unique insights to the basis of substrate specificity in the broad class of diiron monooxygenases that oxidize nonpolar molecules. Studies of parallel pathways will be relevant to other metabolic pathways where toxic metabolites are necessarily produced as part of the metabolism of a growth supporting substrate.