Structure of NADH:Q oxidoreductase from bovine heart mitochondria studied by electron microscopy

Egbert J. Boekema*, Jan F. L. van Breemen, Wilko Keegstra, Ernst F. J. van Bruggen, Simon P. J. Albracht

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review


    Two-dimensional crystalline arrays of NADH:Q oxidoreductase preparations have been obtained by microdiffusion of protein dissolved in detergent against a 15 mM sodium acetate buffer of pH 5.5 containing 10% (wv) ammonium sulphate. Electron microscopy was used to study the structure of negatively stained crystals. Computer-reconstructed images were obtained by the Fourier peak filtering method. The crystals have p4 symmetry and a square unit cell with dimensions of 15.2 ± 0.5 nm. The four asymmetric units in the unit cell form a single tetrameric molecule with a dimension in the third direction of 8.2 nm. It is concluded on the basis of the estimated molecular mass that each tetramer cannot contain more than only one FMN molecule. This implies that the tetramers possibly are only a part of Complex I, since there is much evidence that one functional enzyme molecule of Complex I contains two FMN molecules.
    Original languageEnglish
    Pages (from-to)7-11
    Number of pages5
    JournalBiochimica et biophysica acta
    Issue number1
    Publication statusPublished - 1982

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