Regulation of organohalide respiration in Dehalococcoides mccartyi strains

该项目的主要目的是表征还原脱卤酶（rdh）基因表达的调控机制，该基因表达使Dehalococcoides能够对多种氯有机化合物做出特异性反应并进行多步脱氯反应。本项目将重点研究Dehalococcoides sp.菌株CBDB1基因组中由分散转录为rdhA基因的基因编码的可能调控蛋白的生化研究。将讨论marr型监管机构和双组分系统监管机构的作用。在观察多个rdh基因对特定氯化芳香族化合物反应的差异转录的基础上，将选择假定的marr型调节因子进行生化分析。这些调节因子将异种产生，生物化学特征，以及与rdh基因启动子区域和可能的配体的相互作用进行研究。相关但生理上不同的dehalococoides菌株DCMB5的基因组序列将被注释。菌株DCMB5和CBDB1的基因组、rdh基因转录和蛋白质组的比较分析将与研究集群的其他小组密切合作进行。这些结果将与这两种菌株的脱氯行为相关联，以试图为进一步的关键脱卤酶及其调节因子分配功能，并确定涉及高氯化化合物（如二苯并对二恶英）逐步脱氯的可能的调节级联反应。

The major aim of this project is to characterize the mechanism of regulation of reductive dehalogenase (rdh) gene expression, which enables Dehalococcoides to respond specifically to diverse chloroorganic compounds and to perform multi-step dechlorination reactions. The project will focus on the biochemical study of putative regulatory proteins encoded in the genome of Dehalococcoides sp. strain CBDB1 by genes divergently transcribed to rdhA genes. The roles of MarR-type regulators and of two-component-system regulators will be addressed. Putative MarR-type regulators will be selected for biochemical analysis on the basis of the observation of a differential transcription of the multiple rdh genes in response to specific chlorinated aromatic compounds. The regulators will be heterologously produced, biochemically characterized and the interaction with promoter regions of rdh genes and possible ligands studied. The genome sequence of the related but physiologically distinct Dehalococcoides strain DCMB5 will be annotated. Comparative analyzes of the genomes, rdh gene transcription and the proteomes of strains DCMB5 and CBDB1 will be carried out in close co-operation with other groups of the research cluster. The results will be correlated to the dechlorination behaviour of both strains in an attempt to assign functions to further key dehalogenases and their regulators and to identify possible regulatory cascades involved in the stepwise dechlorination of highly chlorinated compounds such as dibenzo-p-dioxins.