Tsao J, Chapman M S, Agbandje M, Keller W, Smith K, Wu H, Luo M, Smith T J, Rossmann M G, Compans R W
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907.
Science. 1991 Mar 22;251(5000):1456-64. doi: 10.1126/science.2006420.
The three-dimensional atomic structure of a single-stranded DNA virus has been determined. Infectious virions of canine parvovirus contain 60 protein subunits that are predominantly VP-2. The central structural motif of VP-2 has the same topology (an eight-stranded antiparallel beta barrel) as has been found in many other icosahedral viruses but represents only about one-third of the capsid protein. There is a 22 angstrom (A) long protrusion on the threefold axes, a 15 A deep canyon circulating about each of the five cylindrical structures at the fivefold axes, and a 15 A deep depression at the twofold axes. By analogy with rhinoviruses, the canyon may be the site of receptor attachment. Residues related to the antigenic properties of the virus are found on the threefold protrusions. Some of the amino termini of VP-2 run to the exterior in full but not empty virions, which is consistent with the observation that some VP-2 polypeptides in full particles can be cleaved by trypsin. Eleven nucleotides are seen in each of 60 symmetry-related pockets on the interior surface of the capsid and together account for 13 percent of the genome.
一种单链DNA病毒的三维原子结构已被确定。犬细小病毒的感染性病毒粒子含有60个主要为VP - 2的蛋白质亚基。VP - 2的中心结构基序与许多其他二十面体病毒具有相同的拓扑结构（一个八链反平行β桶），但仅占衣壳蛋白的约三分之一。在三重轴上有一个22埃（Å）长的突起，在五重轴处围绕五个圆柱形结构中的每一个有一个15 Å深的峡谷，在二重轴处有一个15 Å深的凹陷。与鼻病毒类似，峡谷可能是受体附着的部位。与病毒抗原特性相关的残基位于三重突起上。VP - 2的一些氨基末端在完整而非空的病毒粒子中伸向外部，这与完整颗粒中的一些VP - 2多肽可被胰蛋白酶切割的观察结果一致。在衣壳内表面的60个对称相关口袋中，每个口袋可见11个核苷酸，它们总共占基因组的13%。
