Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602, USA.
Virology. 2011 Mar 1;411(1):142-52. doi: 10.1016/j.virol.2010.12.005. Epub 2011 Jan 15.
Avian polyomavirus (APV) causes a fatal, multi-organ disease among several bird species. Using cryogenic electron microscopy and other biochemical techniques, we investigated the structure of APV and compared it to that of mammalian polyomaviruses, particularly JC polyomavirus and simian virus 40. The structure of the pentameric major capsid protein (VP1) is mostly conserved; however, APV VP1 has a unique, truncated C-terminus that eliminates an intercapsomere-connecting β-hairpin observed in other polyomaviruses. We postulate that the terminal β-hairpin locks other polyomavirus capsids in a stable conformation and that absence of the hairpin leads to the observed capsid size variation in APV. Plug-like density features were observed at the base of the VP1 pentamers, consistent with the known location of minor capsid proteins VP2 and VP3. However, the plug density is more prominent in APV and may include VP4, a minor capsid protein unique to bird polyomaviruses.
禽多瘤病毒 (APV) 可引起多种鸟类的致命多器官疾病。我们使用低温电子显微镜和其他生化技术研究了 APV 的结构，并将其与哺乳动物多瘤病毒（特别是 JC 多瘤病毒和猿猴病毒 40）进行了比较。五聚体主要衣壳蛋白 (VP1) 的结构大部分保守；然而，APV VP1 具有独特的截断 C 末端，消除了在其他多瘤病毒中观察到的衣壳间连接 β-发夹。我们推测末端 β-发夹将其他多瘤病毒衣壳锁定在稳定构象中，而发夹的缺失导致 APV 中观察到的衣壳大小变化。在 VP1 五聚体的底部观察到类似插头的密度特征，与已知的次要衣壳蛋白 VP2 和 VP3 的位置一致。然而，在 APV 中，插头密度更为突出，可能包括 VP4，这是一种仅存在于鸟类多瘤病毒中的次要衣壳蛋白。
