Hur H G, Sadowsky M J, Wackett L P
Department of Soil Science, University of Minnesota, St. Paul 55108.
Appl Environ Microbiol. 1994 Nov;60(11):4148-54. doi: 10.1128/aem.60.11.4148-4154.1994.
The recombinant bacterium Pseudomonas putida G786(pHG-2) metabolizes pentachloroethane to glyoxylate and carbon dioxide, using cytochrome P-450CAM and toluene dioxygenase to catalyze consecutive reductive and oxidative dehalogenation reactions (L.P. Wackett, M.J. Sadowsky, L.N. Newman, H.-G. Hur, and S. Li, Nature [London] 368:627-629, 1994). The present study investigated metabolism of brominated and chlorofluorocarbon compounds by the recombinant strain. Under anaerobic conditions, P. putida G786(pHG-2) reduced 1,1,2,2-tetrabromoethane, 1,2-dibromo-1,2-dichloroethane, and 1,1,1,2-tetrachloro-2,2-difluoroethane to products bearing fewer halogen substituents. Under aerobic conditions, P. putida G786(pHG-2) oxidized cis- and trans-1,2-dibromoethenes, 1,1-dichloro-2,2-difluoroethene, and 1,2-dichloro-1-fluoroethene. Several compounds were metabolized by sequential reductive and oxidative reactions via the constructed metabolic pathway. For example, 1,1,2,2-tetrabromoethane was reduced by cytochrome P-450CAM to 1,2-dibromoethenes, which were subsequently oxidized by toluene dioxygenase. The same pathway metabolized 1,1,1,2-tetrachloro-2,2-difluoroethane to oxalic acid as one of the final products. The results obtained in this study indicate that P. putida G786(pHG-2) metabolizes polyfluorinated, chlorinated, and brominated compounds and further demonstrates the value of using a knowledge of catabolic enzymes and recombinant DNA technology to construct useful metabolic pathways.
重组细菌恶臭假单胞菌G786(pHG - 2)利用细胞色素P - 450CAM和甲苯双加氧酶催化连续的还原和氧化脱卤反应，将五氯乙烷代谢为乙醛酸和二氧化碳（L.P. 瓦克特、M.J. 萨多夫斯基、L.N. 纽曼、H.-G. 胡尔和S. 李，《自然》[伦敦]368:627 - 629，1994年）。本研究调查了该重组菌株对溴化和氯氟烃化合物的代谢情况。在厌氧条件下，恶臭假单胞菌G786(pHG - 2)将1,1,2,2 - 四溴乙烷、1,2 - 二溴 - 1,2 - 二氯乙烷和1,1,1,2 - 四氯 - 2,2 - 二氟乙烷还原为卤素取代基较少的产物。在需氧条件下，恶臭假单胞菌G786(pHG - 2)氧化顺式和反式1,2 - 二溴乙烯、1,1 - 二氯 - 2,2 - 二氟乙烯和1,2 - 二氯 - 1 - 氟乙烯。几种化合物通过构建的代谢途径经连续的还原和氧化反应进行代谢。例如，细胞色素P - 450CAM将1,1,2,2 - 四溴乙烷还原为1,2 - 二溴乙烯，随后甲苯双加氧酶将其氧化。同一途径将1,1,1,2 - 四氯 - 2,2 - 二氟乙烷代谢为草酸作为最终产物之一。本研究获得的结果表明，恶臭假单胞菌G786(pHG - 2)能代谢多氟、氯代和溴代化合物，并进一步证明了利用分解代谢酶知识和重组DNA技术构建有用代谢途径的价值。
