Shown is an image of the T4 virus studied by Michael Rossmann’s group. The virus carries its genetic material in the head section, then injects it into the E. coli bacterium through its tail after the baseplate attaches itself to the cell membrane. (Graphic/Purdue University Department of Biology)
A publication-quality graphic is available at http://ftp.purdue.edu/pub/uns/rossmann.baseplate2.jpeg.