P14 Volker Müller
ATP synthases are key elements in cellular bioenergetics. They developed very early in evolution but still little is known about ATP synthases from life forms such as archaea or bacteria that have an ancient life style. Our own preparatory work revealed unique ATP synthases with unprecedented subunit composition, unique biochemical features and ion-binding sites in archaea and the acetogenic bacterium Acetobacterium woodii that have evolved to allow growth under extreme energy limitation. The heterologous and homologous expression systems that we have set up enables us to address the structure/function relationship of these unique enzymes by mutational analyses followed by biochemical, bioenergetic and biophysical studies. In particular we will focus on the structure of the entire archaeal A1AO ATP synthase and its subcomplexes, the number of c subunits and ion-binding sites in the motor and the evolution of the ion-binding site from Na+ over Na+ + H+ to H+ in the membrane-embedded motor. For the Na+ F1FO ATP synthase of A. woodii, we will unravel the structure of the unique FOVO hybrid rotor, the role of the different rotor subunits in ion transport and rotor assembly, the rotor dynamics and explore the evolutionary advantage of the FOVO hybrid rotor with its decreased Na+/ATP stoichiometry.
High-resolution AFM topographs (A-C) and electron micrographs (D) of reconstituted c rings from Acebacterium woodii. Each ring is either neighbored by rings either exposing their wide or narrow ends. Reference free correlation averages of the different assemblies revealed 11 masses forming wide and narrow end of the rings. (D) shows a projection map of 13 merged images at 5 Å resolution. One unit cell of plane group p22,2, with its symmetry elements (two-fold rotation axes and screw axes) is indicated. The unit cell measures 100.3 x 108 Å and contains four c rings.
Structural model of the A1Ao ATP synthase from Pyrococcus furiosus based on single particle analyses. X-ray structures of subunits from F- or A-ATP synthases were fitted into the map. The a subunit is given in yellow, the two peripheral stalks are made by EH-dimers (pink), and the size of the Ao domain is sufficient to harbour the 16-hairpin c-ring from Enterococcus hirae.
Schlegel, K., Leone, V., Faraldo-Gómez, J.D. and Müller, V. (2012) Promiscuous archaeal ATP synthase concurrently coupled to Na+ and H+ translocation. Proc Natl Acad Sci USA 109, 947-952.
Hunke, C., Antosch, M., Müller, V. and Grüber, G. (2011) Binding of subunit E into the A-B interface of the A1AO ATP synthase. Biochim Biophys Acta 1808, 2111-2118.
Biegel, E. and Müller, V. (2010) Bacterial Na+-translocating ferredoxin:NAD+ oxidoreductase. Proc Natl Acad Sci USA 107, 18138-18142.
Biegel, E. and Müller, V. (2011) A Na+-translocating pyrophosphatase in the acetogenic bacterium Acetobacterium woodii. J Biol Chem 286, 6080-6084.
Küper, U., Meyer, C., Müller, V., Rachel, R. and Huber, H. (2010) Energized outer membrane and spatial separation of metabolic processes in the hyperthermophilic Archaeon Ignicoccus hospitalis. Proc Natl Acad Sci USA 107, 3152-3156.
Saum, R., Schlegel, K., Meyer, B. and Müller, V. (2009) The F1FO ATP synthase genes in Methanosarcina acetivorans are dispensable for growth and ATP synthesis. FEMS Microbiol Lett 300, 230-236.
Vonck, J., Pisa, K. Y., Morgner, N., Brutschy, B. and Müller, V. (2009) Three-dimensional structure of A1AO ATP synthase from the hyperthermophilic archaeon Pyrococcus furiosus by electron microscopy. J Biol Chem 284, 10110-10119.
Fritz, M., Klyszejko, A.L., Morgner, N., Vonck, J., Brutschy, B., Müller, D.J., Meier. T. and Müller, V. (2008) An intermediate step in the evolution of ATPases: a hybrid FO-VO rotor in a bacterial Na+ F1FO ATP synthase. FEBS J 275, 1999-2007.