Evidence for modified mechanisms of chloroethene oxidation in Pseudomonas butanovora mutants containing single amino acid substitutions in the hydroxylase alpha-subunit of butane monooxygenase.
Evidence for modified mechanisms of chloroethene oxidation in Pseudomonas butanovora mutants containing single amino acid substitutions in the hydroxylase alpha-subunit of butane monooxygenase.
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丁烷单加氧酶羟化酶 α 亚基中含有单个氨基酸取代的丁酸假单胞菌突变体中氯乙烯氧化机制改变的证据。
DOI：
10.1128/jb.00189-07
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发表时间：
2007
影响因子：
3.2
通讯作者：
Arp,DanielJ
中科院分区：
文献类型：
--
作者：
Halsey,KimberlyH;Doughty,DavidM;Sayavedra-Soto,LuisA;Bottomley,PeterJ;Arp,DanielJ
研究了丁烷单加氧酶羟化酶(BMOH-α) α-亚基单氨基酸取代的3株丁醇假单胞菌与野生型菌株（Rev WT）对二氯乙烯（DCE）和三氯乙烯（TCE）的氧化性能。突变菌株G113N对三种氯乙烯（CEs）的氧化速率降低，最大丁烷氧化速率降低。突变菌株L279F的TCE降解率降低了一半，而DCE氧化率与Rev WT相同。证据表明，Rev WT与某些突变菌株之间CE氧化产物的组成不同。例如，Rev WT在CE氧化过程中释放了几乎所有的有效氯，而菌株F321Y在1,2-顺式DCE和TCE氧化过程中释放了约40%的氯，菌株G113N在DCE氧化过程中释放了14 - 25%的有效氯，在TCE氧化过程中释放了56%的有效氯。而Rev WT、菌株L279F和菌株F321Y在氧化1,2-顺式dce过程中形成了化学计量量的1,2-顺式dce环氧化物，而菌株G113N氧化的1,2-顺式dce中只有约50%被检测为环氧化物。结果表明，1,2-顺式dce环氧化物是丁烷单加氧酶（BMO）的底物，该底物在母体化合物消耗后被氧化。然而，所有突变菌株释放的可用的1,2-顺式dce氯不到40%，这表明它们对环氧化物的活性发生了变化。此外，菌株G113N不能降解环氧化物。Rev WT和菌株F321Y暴露于TCE时检测到环氧化TCE，而菌株L279F和G113N未检测到环氧化TCE。在突变菌株中，乳酸依赖的o2摄取速率受到DCE降解的不同影响，这提供了证据，表明改变的BMOs释放的一些产物降低了CE对细胞毒性的影响。ce与p复合作为衬底的应用。butanovoraBMOH-α突变体可能有助于了解BMO的催化机制。
The properties of oxidation of dichloroethene (DCE) and trichloroethylene (TCE) by three mutant strains ofPseudomonas butanovoracontaining single amino acid substitutions in the α-subunit of butane monooxygenase hydroxylase (BMOH-α) were compared to the properties of the wild-type strain (Rev WT). The rates of oxidation of three chloroethenes (CEs) were reduced in mutant strain G113N and corresponded with a lower maximum rate of butane oxidation. The rate of TCE degradation was reduced by one-half in mutant strain L279F, whereas the rates of DCE oxidation were the same as those in Rev WT. Evidence was obtained that the composition of products of CE oxidation differed between Rev WT and some of the mutant strains. For example, while Rev WT released nearly all available chlorine stoichiometrically during CE oxidation, strain F321Y released about 40% of the chlorine during 1,2-cis-DCE and TCE oxidation, and strain G113N released between 14 and 25% of the available chlorine during oxidation of DCE and 56% of the available chlorine during oxidation of TCE. Whereas Rev WT, strain L279F, and strain F321Y formed stoichiometric amounts of 1,2-cis-DCE epoxide during oxidation of 1,2-cis-DCE, only about 50% of the 1,2-cis-DCE oxidized by strain G113N was detected as the epoxide. Evidence was obtained that 1,2-cis-DCE epoxide was a substrate for butane monooxygenase (BMO) that was oxidized after the parent compound was consumed. Yet all of the mutant strains released less than 40% of the available 1,2-cis-DCE chlorine, suggesting that they have altered activity towards the epoxide. In addition, strain G113N was unable to degrade the epoxide. TCE epoxide was detected during exposure of Rev WT and strain F321Y to TCE but was not detected with strains L279F and G113N. Lactate-dependent O2uptake rates were differentially affected by DCE degradation in the mutant strains, providing evidence that some products released by the altered BMOs reduced the impact of CE on cellular toxicity. The use of CEs as substrates in combination withP. butanovoraBMOH-α mutants might allow insights into the catalytic mechanism of BMO to be obtained.