High-level transcription of large gene regions: a novel T 7 RNA-polymerase-based system for expression of functional hydrogenases in the phototrophic bacterium Rhodobacter capsulatus

High-level synthesis of complex enzymes like bacterial [NiFe] hydrogenases, in general, requires an expression system that allows concerted expression of a large number of genes. So far, it has not been possible to overproduce a hydrogenase in a stable and active form by using a customary expression system. Therefore we started to establish a new, T 7 -based expression system in the phototrophic bacterium Rhodobacter capsulatus . The beneficial properties of this bacterial host in combination with the unique capacity of T 7 RNA polymerase to synthesize long transcripts will allow the high-level synthesis and assembly of active hydrogenase as well as other complex enzymes in the near future.