An immunodominant N-terminal region of VP1 protein of poliovirion that is buried in crystal structure can be exposed in solution.

According to previous X-ray crystallographic analyses of poliovirus structure, the amino terminal region of the capsid protein VP1 is inside the capsid shell. We have found that antibodies to synthetic peptides derived from an immunodominant part of this region readily precipitate intact infectious virions, indicating that in solution, the virus can assume a conformation that is partially different from that seen in the crystal structure. We propose that this part of VP1 is alternating between two conformations.