DNA-induced structural changes in the papillomavirus capsid

Human papillomavirus capsid assembly requires intercapsomeric disulfide bon ds between molecules of the major capsid protein L1. Virions isolated from naturally occurring lesions have a higher degree of cross-linking than viru s-like particles (VLPs), which have been generated in eukaryotic expression systems. Here we show that DNA encapsidation into VLPs leads to increased cross-linking between L1 molecules comparable to that seen in virions. A hi gher trypsin resistance, indicating a tighter association of capsomeres thr ough DNA interaction, accompanies this structural change.