An electron-microscope study of beta-glucuronidase crystals.

beta-Glucuronidase from rat preputial glands was crystallized as thin sheets having p6 symmetry in projection with a equal 20.2nm. A filtered image was produced by Fourier methods to a resolution of 2.2 nm by averaging information from six areas. This suggests an approximately triangular molecular outline in projection, and this is taken to indicate a probable tetrahedral arrangement of the four subunits of the beta-glucuronidase molecule.