Structure of small virus-like particles assembled from the L1 protein of human papillomavirus 16

The papillomavirus major late protein, L1, forms the pentameric assembly un it of the viral shell. Recombinant HPV16 L1 pentamers assemble in vitro int o capsid-like structures, and truncation of ten N-terminal residues leads t o a homogeneous preparation of 12-pentamer, icosahedral particles. X-ray cr ystallographic analysis of these particles at 3.5 Angstrom resolution shows that L1 closely resembles VP1 from polyomaviruses. Surface loops contain t he sites of sequence variation among HPV types and the locations of dominan t neutralizing epitopes. The ease with which small virus-like particles may be obtained from L1 expressed in E. coli makes them attractive candidate c omponents of a papillomavirus vaccine. Their crystal structure also provide s a starting point for future vaccine design.