Halorespiration is a novel type of anaerobic energy transduction in which both aliphatic and aromatic chlorinated compounds act as terminal electron acceptor. The key enzyme of this respiratory pathway represents a novel family of iron-sulfur and corrinoid-containing reductases. Both chlorophenol reductase (CPR) and chloroethene reductase (CER) have been purified from the gram-positive bacterium Desulfitobacterium spp., and the corresponding genes have been isolated. The proposed research aims at the elucidation of structure-function relations in both types of dehaloreductases, addressing features that relate to reaction mechanism and substrate specificity.
Aim of project The recent development of a genetic system for D. dehalogenans enables the generation of a knock-out mutant of the chlorophenol reductase, which will be a suitable host for functional overproduction of wild type and mutant CPR-type reductases ( e.g. mutants with disrupted binding sites for iron-sulfur centers and corrinoid). Besides, CER of Dehalospirillum sp. will be produced in D.dehalogenans as well, because the catalytic subunit has some unique features that are anticipated to be relevant for high-resolution structural analysis. In addition, random mutagenesis of a set of dehaloreductases from Dehalococcides ethenogenes will be performed by DNA family shuffling, with the aim to reveal determinants of substrate specificity |
