Three-dimensional reconstruction of the shape of human wart virus using spatial correlations

Correlation averaging was used to enhance the three-dimensional spherical harmonic expansion of human wart virus particles from randomly-oriented negatively-stained electron microscopic images in holey grids. The reconstruction reveals the coat protein arrangement and variations in stain distribution inside the virus core. Selection rules imposed by the spherical symmetry on the harmonic expansion component are obtained indeed for angular momenta, l, lower than 11, but cannot be shown for l greater than or equal to 11, due to non-spherical distortions of about 1/11th of the radius of the virus. This prevents us from resolving fine details of packing of the protomers on the surface lattice. Distribution of stain inside the virus core, and its spherical symmetry, is reconstructed and may be related to nucleic acids and core protein structure.