Biochemical and molecular characterization of a tetrachloroethene dechlorinating Desulfitobacterium sp strain Y51:: a review
Biochemical and molecular characterization of a tetrachloroethene dechlorinating Desulfitobacterium sp strain Y51:: a review
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DOI：
10.1007/s10295-005-0252-z
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发表时间：
2005-12-01
影响因子：
3.4
通讯作者：
Goto, M
中科院分区：
文献类型：
--
作者：
Furukawa, K;Suyama, A;Goto, M
一种严格厌氧细菌，脱硫杆菌属菌株Y51，能够在高至960 μ M和低至0.06 μ M的浓度下，通过三氯乙烯（TCE）将四氯乙烯（PCE）非常有效地脱氯为顺式-1，2-二氯乙烯（cis-DCE）。脱氯非常容易受到空气氧化和潜在的替代电子受体，如亚硝酸盐、硝酸盐或亚硫酸盐的影响。对菌株Y51的PCE还原脱卤酶（由pceA基因编码，简称PceA脱卤酶）进行了纯化和性质研究。纯化的酶催化PCE还原脱氯为cis-DCE的比活性为113.6 nmol min（-1）mg protein（-1）。PCE和TCE的表观Km值分别为105.7和535.3 μ M。除PCE和TCE外，该酶还对六氯乙烷、五氯乙烷、1，1，1，2-四氯乙烷和1，1，2，2-四氯乙烷等氯代乙烷具有脱氯活性。从Y51基因组克隆的8.4 kb DNA片段显示了8个开放阅读框，包括pceA B基因。免疫印迹分析表明，PceA脱卤酶是本地化的周质的Y51细胞。PceA脱卤酶的产生在添加TCE时被诱导。在cis-DCE存在下，观察到菌株Y51的显著生长抑制，更有趣的是，当细胞与cis-DCE一起生长时，pce基因簇以高频率被删除。
A strict anaerobic bacterium, Desulfitobacterium sp. strain Y51, is capable of very efficiently dechlorinating tetrachloroethene (PCE) via trichloroethene (TCE) to cis-1,2-dichloroethene (cis-DCE) at concentrations as high as 960 mu M and as low as 0.06 mu M. Dechlorination was highly susceptible to air oxidation and to potential alternative electron acceptors, such as nitrite, nitrate or sulfite. The PCE reductive dehalogenase (encoded by the pceA gene and abbreviated as PceA dehalogenase) of strain Y51 was purified and characterized. The purified enzyme catalyzed the reductive dechlorination of PCE to cis-DCE at a specific activity of 113.6 nmol min(-1) mg protein(-1). The apparent K-m values for PCE and TCE were 105.7 and 535.3 mu M, respectively. In addition to PCE and TCE, the enzyme exhibited dechlorination activity for various chlorinated ethanes such as hexachloroethane, pentachloroethane, 1,1,1,2-tetrachloroethane and 1,1,2,2-tetrachloroethane. An 8.4-kb DNA fragment cloned from the Y51 genome revealed eight open reading frames, including the pceA B genes. Immunoblot analysis revealed that PceA dehalogenase is localized in the periplasm of Y51 cells. Production of PceA dehalogenase was induced upon addition of TCE. Significant growth inhibition of strain Y51 was observed in the presence of cis-DCE, More interestingly, the pce gene cluster was deleted with high frequency when the cells were grown with cis-DCE.