Assembly of the Streptomyces coelicolor Rieske protein

• Applicant: Dr. Rebecca Keller
• Subject Area: Metabolism, Biochemistry and Genetics of Microorganisms
• Term: from 2009 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 153376249

Protein export and assembly is essential in bacteria, which is managed by two distinct operating translocases, called the Sec and the Tat system. An important Tat-dependent protein is the Rieske Protein, an essential component of the essential energy transduction bc1complex in the respiratory chain of many bacteria. Interestingly, in Actinomycetes like Streptomyces coelicolor and other pathogenic organisms the Rieske Protein is composed of three transmembrane domains (TM) instead of one prior to the iron sulphur domain and very unusually it has an internal Tat (twin arginine) motif localized in the third transmembrane domain. To investigate the pathway by which the first two transmembrane helices of the 3TM Rieske protein are assembled into the membrane and the recognition of an internal signal sequence by the Tat machinery an engineered reporter system will be used, whereby the iron sulphur domain of the Rieske protein is replaced. When expressed in different E. coli depletion strains its localization via pulse chase and protease digestion experiments will be analyzed. Then the effect of different truncations and fusions of the Rieske protein will give deeper impacts. The function of the extended membrane protein of the S. coelicolor Rieske protein will be investigated by using a mutant strain of S. coelicolor, which should be blocked in the electron flow of the bc1 complex. Complementation studies and further biochemical analysis shed light on the function and the organization of the complex.

• DFG Programme: Research Fellowships
• International Connection: United Kingdom
• Host: Professorin Tracy Palmer, Ph.D.