Sapp M, Fligge C, Petzak I, Harris J R, Streeck R E
Institute for Medical Microbiology and Hygiene, University of Mainz, D-55101 Mainz, Germany.
J Virol. 1998 Jul;72(7):6186-9. doi: 10.1128/JVI.72.7.6186-6189.1998.
We have used viruslike particles (VLPs) of human papillomaviruses to study the structure and assembly of the viral capsid. We demonstrate that mutation of either of two highly conserved cysteines of the major capsid protein L1 to serine completely prevents the assembly of VLPs but not of capsomers, whereas mutation of all other cysteines leaves VLP assembly unaffected. These two cysteines form intercapsomeric disulfides yielding an L1 trimer. Trimerization comprises about half of the L1 molecules in VLPs but all L1 molecules in complete virions. We suggest that trimerization of L1 is indispensable for the stabilization of intercapsomeric contacts in papillomavirus capsids.
我们利用人乳头瘤病毒的病毒样颗粒（VLPs）来研究病毒衣壳的结构和组装。我们证明，主要衣壳蛋白L1的两个高度保守的半胱氨酸中的任何一个突变为丝氨酸，都会完全阻止VLPs的组装，但不会阻止衣壳粒的组装，而其他所有半胱氨酸的突变则不会影响VLP的组装。这两个半胱氨酸形成衣壳间二硫键，产生L1三聚体。三聚化在VLPs中约占一半的L1分子，但在完整病毒体中占所有L1分子。我们认为，L1的三聚化对于乳头瘤病毒衣壳中衣壳间接触的稳定是必不可少的。
