title: A novel T7 RNA polymerase dependent expression system for high-level protein production in the phototrophic bacterium Rhodobacter capsulatus.
abstract: The functional expression of heterologous genes using standard bacterial expression hosts such as Escherichia coli is often limited, e.g. by incorrect folding, assembly or targeting of recombinant proteins. Consequently, alternative bacterial expression systems have to be developed to provide novel strategies for protein synthesis exceeding the repertoire of the standard expression host E. coli. Here, we report on the construction of a novel expression system that combines the high processivity of T7 RNA polymerase with the unique physiological properties of the facultative photosynthetic bacterium Rhodobacter capsulatus. This system basically consists of a recombinant R. capsulatus T7 expression strain (R. capsulatus B10S-T7) harboring the respective polymerase gene under control of a fructose inducible promoter. In addition, a set of different broad-host-range vectors (pRho) was constructed allowing T7 RNA polymerase dependent and independent target gene expression in R. capsulatus and other Gram-negative bacteria. The expression efficiency of the novel system was studied in R. capsulatus and E. coli using the yellow fluorescent protein (YFP) as model protein. Expression levels were comparable in both expression hosts and yielded up to 80mg/l YFP in phototrophically grown R. capsulatus cultures. This result clearly indicates that the novel R. capsulatus-based expression system is well suited for the high-level expression of soluble proteins.
authors.affiliation: Institute of Molecular Enzyme Technology, Heinrich-Heine-University Duesseldorf, Forschungszentrum Juelich, Stetternicher Forst, D-52426 Juelich, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Katzke
authors.forename: Solmaz
authors.initials: S
authors.lastname: Arvani
authors.forename: René
authors.initials: R
authors.lastname: Bergmann
authors.forename: Franco
authors.initials: F
authors.lastname: Circolone
authors.forename: Annette
authors.initials: A
authors.lastname: Markert
authors.forename: Vera
authors.initials: V
authors.lastname: Svensson
authors.forename: Karl-Erich
authors.initials: KE
authors.lastname: Jaeger
authors.forename: Achim
authors.initials: A
authors.lastname: Heck
authors.forename: Thomas
authors.initials: T
authors.lastname: Drepper
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D016354:Rhodobacter capsulatus / Q000378:metabolism*; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D008164:Luminescent Proteins; D014764:Viral Proteins; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases