The nine C-terminal amino acids of the major capsid protein of the human papillomavirus type 16 are essential for DNA binding and gene transfer capacity.

Four C-terminal deletion mutants of the human papillomavirus 16 L1 protein were expressed in the baculovirus expression system. They consist of the deletion of amino acids 497-505, 477-505, 403-505 and 302-505 (delta C9, delta C31, delta C103 and delta C204 respectively). Only two of the C-terminally deleted proteins, delta C9 and delta C31, retained the ability to form virus-like particles (VLPs) resembling those obtained with the full length L1 protein. Analysis of deleted L1 proteins and corresponding VLPs indicated that the C-terminus was necessary both for DNA binding and DNA packaging. These results were corroborated by the loss of the gene transfer capacities of C-terminal deleted VLPs.