Transport of Nitrate and Nitrite across Cell Membranes

• Antragstellerinnen / Antragsteller: Professorin Dr. Susana Andrade; Professor Dr. Oliver Einsle
• Fachliche Zuordnung: Stoffwechselphysiologie, Biochemie und Genetik der Mikroorganismen
• Förderung: Förderung von 2007 bis 2019
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 54268421

Within the biogeochemical nitrogen cycle, three distinct membrane transport systems exist for the key metabolites nitrate (NO3-), nitrite (NO2-) and ammonium (NH4+). In extension of our previous work on ammonium transporters we now propose to investigate the properties of the two classes of nitrate and nitrite transport proteins, a nitrate/nitrite antiporter belonging to the major facilitator family of secondary active transporters (NarK, NarU) and a proton/nitrite symporter that is a member of the fumarate-nitrite transporter family (NirC). Both types of proteins are typical and important representatives of their families and information gained on them will be of general relevance for our understanding of the function of secondary active transporters. We have recombinantly expressed, solubilized and purified the three proteins NarK, NarU and NirC from Escherichia coli, and we are initiating structural and functional studies in order to elucidate their architecture and transport mechanism. A prime goal will be to solve the crystal structures of all proteins, if possible in different, substrate-bound states and conformations. Furthermore, the purified proteins are to be reconstituted into artificial membrane systems and used for functional studies of transport and dependence on membrane potential and proton gradients. For such studies, both proteoliposomes and planar lipid bilayers are available and will be used.

• DFG-Verfahren: Sachbeihilfen