UC San Diego

Cryo-electron microscopy and image analysis techniques make it possible to study structural and functional relationships of macromolecular complexes that currently are not easily examined with crystallographic techniques. We have recorded images of frozen-hydrated human rhinovirus serotype-14 (HRV-14) complexed with a neutralizing, monoclonal, antibody fragment (Fab-17Ia; Fig. 1 A); and HRV-16 complexed with the amino-terminal, two-domain fragment (D1D2) of its cellular receptor (intercellular adhesion molecule-1, ICAM-1; Fig. 1B). Three-dimensional reconstructions (Figs. 2A,B) were calculated to ∽3nm resolution from 35 and 44 images of each complex, respectively. The HRV-14/Fab structure clearly identified the footprint of the Fab on the surface of the virion. The HRV-16/D1D2 reconstruction presents, for the first time, the three-dimensional structure of a complete virus complexed with its cellular receptor.