3-DIMENSIONAL STRUCTURE OF F1-ATPASE OF THERMOPHILIC BACTERIUM PS3 OBTAINED BY ELECTRON CRYSTALLOGRAPHY

The three-dimensional molecular structure of the F1-ATPase from a thermophilic bacterium PS3 (TF1) at 3 nm resolution was reconstructed from a series of tilted, negatively stained electron microscopic images of two-dimensional crystals which were formed on a clean surface of mercury. It was shown that six ellipsoidal columns, each approximately 7 nm in length and approximately 3 nm in diameter, corresponding to the alpha and beta subunits, surrounded a central hollow cavity of approximately 2.8 nm in diameter. The cavity, however, did not penetrate the molecule, and a mass, most likely the gamma subunit, existed in the cavity at a depth of approximately 3.4 nm from the top.