Abstract
Rotational power spectrum analysis of scanning transmission electron micrographs of negatively stained herpesvirus capsids has given direct evidence for the 6-fold symmetry of the herpesvirus hexon capsomere. Individual hexons have been analyzed in situ without interference from other parts of the capsid because only one level of the capsid was in focus in the micrograph. This study found hexons to have 6-fold symmetry. The majority of the mass of each hexon subunit was seen to lie on a line connecting the centers of adjacent capsomeres. This agrees with analysis of conventional micrographs of capsid fragments, which are also presented, as well as with biochemical data and theoretical expectations.