Electron microscopic characterization of helical filaments formed by subunits I and II (core proteins) of ubiquinol: cytochrome c reductase from Neurospora mitochondria.

The isolated and water-soluble complex of subunits I and II (core proteins) of ubiquinone:cytochrome c reductase from Neurospora mitochondria forms filaments below pH 6.0. Three independent helical reconstructions of single filaments were compared with the 3-D reconstruction of the native enzyme. A model for the helix is proposed in which the core complex dimers are arranged radially with the face which is proximal to the membrane in the native enzyme on the outside of the helix. The dimension of the core complex dimer perpendicular to the helix axis (70 A) provides an independent estimate of the height of the core complex to that obtained previously from cytochrome reductase crystals. The results of STEM mass measurement and the helical model give a mass per repeating unit of 90 kDa, which would indicate that the monomeric core complex consists of one 45-kDa and one 50-kDa subunit.

[1]  S. Perkins,et al.  Low-resolution structural studies of mitochondrial ubiquinol:cytochrome c reductase in detergent solutions by neutron scattering. , 1983, Journal of molecular biology.

[2]  Anthony N. Martonosi,et al.  The Enzymes of Biological Membranes , 1985, Springer US.

[3]  E. C. Slater,et al.  Polypeptide composition of purified QH2:cytochrome c oxidoreductase from beef-heart mitochondria. , 1977, Biochimica et biophysica acta.

[4]  S. Hovmöller,et al.  Structural studies of cytochrome reductase. Improved membrane crystals of the enzyme complex and crystallization of a subcomplex. , 1983, Journal of molecular biology.

[5]  Y. Hatefi,et al.  Studies on the electron transfer system. XLI. Reduced coenzyme Q (QH2)-cytochrome c reductase. , 1962, The Journal of biological chemistry.

[6]  S. Hovmöller,et al.  Structural studies of cytochrome reductase. Subunit topography determined by electron microscopy of membrane crystals of a subcomplex. , 1983, Journal of molecular biology.

[7]  Y. Hatefi.  The mitochondrial electron transport and oxidative phosphorylation system. , 1985, Annual review of biochemistry.

[8]  T. Arad,et al.  Three-dimensional structure of ubiquinol:cytochrome c reductase from Neurospora mitochondria determined by electron microscopy of membrane crystals. , 1981, Journal of molecular biology.

[9]  L. Grivell,et al.  Subunit II of yeast QH2:cytochrome-c oxidoreductase. Nucleotide sequence of the gene and features of the protein. , 1987, European journal of biochemistry.

[10]  U. K. Laemmli,et al.  Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4 , 1970, Nature.

[11]  R. Freeman,et al.  Comparative mass measurement of biological macromolecules by scanning transmission electron microscopy , 1981, Journal of microscopy.

[12]  S. Hovmöller,et al.  Membrane crystals of a subunit complex of mitochondrial cytochrome reductase containing the cytochromes b and c 1 , 1981, FEBS letters.

[13]  H. Weiss,et al.  Isolation of mitochondrial succinate: ubiquinone reductase, cytochrome c reductase and cytochrome c oxidase from Neurospora crassa using nonionic detergent. , 1979, European journal of biochemistry.

[14]  E. Stadtman,et al.  Regulation of glutamine synthetase. XII. Electron microscopy of the enzyme from Escherichia coli. , 1968, Biochemistry.

[15]  J. Berriman,et al.  Methods for specimen thickness determination in electron microscopy. II. Changes in thickness with dose. , 1986, Ultramicroscopy.

[16]  R. Steinbrecht,et al.  Cryotechniques in Biological Electron Microscopy , 1987, Springer Berlin Heidelberg.

[17]  J. Lepault,et al.  Three-dimensional structure of unstained, frozen-hydrated extended tails of bacteriophage T4. , 1985, Journal of molecular biology.

[18]  E. Egelman,et al.  An algorithm for straightening images of curved filamentous structures. , 1986, Ultramicroscopy.

[19]  D. DeRosier,et al.  Reconstruction of three-dimensional images from electron micrographs of structures with helical symmetry. , 1970, Journal of molecular biology.

[20]  T. Arad,et al.  Membrane crystals of ubiquinone:cytochrome c reductase from Neurospora mitochondria , 1979, Nature.

[21]  W. Neupert,et al.  A family of mitochondrial proteins involved in bioenergetics and biogenesis , 1989, Nature.

[22]  H. Weiss,et al.  Dimeric ubiquinol:cytochrome c reductase of Neurospora mitochondria contains one cooperative ubiquinone-reduction centre. , 1986, European journal of biochemistry.