Characterisation of PduS, the pdu metabolosome corrin reductase, and evidence of substructural organisation within the bacterial microcompartment.
Characterisation of PduS, the pdu metabolosome corrin reductase, and evidence of substructural organisation within the bacterial microcompartment.
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DOI：
10.1371/journal.pone.0014009
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发表时间：
2010-11-16
期刊：
影响因子：
3.7
通讯作者：
Warren MJ
中科院分区：
文献类型：
--
作者：
Parsons JB;Lawrence AD;McLean KJ;Munro AW;Rigby SE;Warren MJ
PduS是咕啉还原酶，并且是钴胺素依赖性二醇脱氢酶的再活化所需的。它是在大丙二醇利用（pdu）操纵子内编码的一种组分，其负责在自组装蛋白质细菌微区室内催化1，2-丙二醇。该酶负责二醇脱氢酶所需的钴胺素辅酶的再活化。克隆了弗氏柠檬酸杆菌钴胺素还原酶（pduS）基因，使该蛋白在大肠杆菌中重组过量生产。大肠杆菌的N-末端His标签。纯化的重组PduS被证明是一个黄素蛋白与非共价结合的FMN，也含有两个耦合的[4Fe-4S]中心。它是一种NADH依赖性黄素还原酶，能够介导cob（III）alamin至cob（II）alamin和cob（II）alamin至cob（I）alamin的单电子还原。[4Fe-4S]中心对氧不稳定，它们的存在影响黄素的中点氧化还原电位。有证据表明，PduS是能够结合钴胺素，这是不一致的观点，PduS仅仅是一个黄素还原酶。PduS还显示与代谢体的壳蛋白之一PduT相互作用，PduT也被认为含有[Fe-S]簇。PduS被证明是作为一个咕啉还原酶，其与壳蛋白的相互作用可以允许电子通过细菌微区室。
PduS is a corrin reductase and is required for the reactivation of the cobalamin-dependent diol dehydratase. It is one component encoded within the large propanediol utilisation (pdu) operon, which is responsible for the catabolism of 1,2-propanediol within a self-assembled proteinaceous bacterial microcompartment. The enzyme is responsible for the reactivation of the cobalamin coenzyme required by the diol dehydratase. The gene for the cobalamin reductase from Citrobacter freundii (pduS) has been cloned to allow the protein to be overproduced recombinantly in E. coli with an N-terminal His-tag. Purified recombinant PduS is shown to be a flavoprotein with a non-covalently bound FMN that also contains two coupled [4Fe-4S] centres. It is an NADH-dependent flavin reductase that is able to mediate the one-electron reductions of cob(III)alamin to cob(II)alamin and cob(II)alamin to cob(I)alamin. The [4Fe-4S] centres are labile to oxygen and their presence affects the midpoint redox potential of flavin. Evidence is presented that PduS is able to bind cobalamin, which is inconsistent with the view that PduS is merely a flavin reductase. PduS is also shown to interact with one of the shell proteins of the metabolosome, PduT, which is also thought to contain an [Fe-S] cluster. PduS is shown to act as a corrin reductase and its interaction with a shell protein could allow for electron passage out of the bacterial microcompartment.