Regulation of organohalide respiration in Dehalococcoides mccartyi strains

本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，该基因表达使脱卤球菌能够特异性地响应于不同的氯代有机化合物并进行多步脱氯反应。该项目将集中于对Dehalococcoides sp.菌株CBDB 1基因组中编码的推定调节蛋白进行生物化学研究，这些蛋白由不同转录为rdhA基因的基因编码。将讨论MarR型调节器和双组分系统调节器的作用。假定的MarR型监管机构将选择生化分析的基础上观察的差异转录的多个rdh基因在响应特定的氯代芳香族化合物。这些调节子将被异源产生，生化特性和与rdh基因启动子区域和可能的配体的相互作用研究。将注释相关但生理上不同的Dehalococcoides菌株DCMB 5的基因组序列。将与研究组的其他小组密切合作，对DCMB 5和CBDB 1菌株的基因组、rdh基因转录和蛋白质组进行比较分析。结果将相关的脱氯行为的两种菌株，试图分配功能，进一步的关键脱卤酶和他们的监管机构，并确定可能的监管级联参与逐步脱氯的高氯化化合物，如二苯并二恶英。

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.