A conformational switch involved in maturation of Staphylococcus aureus bacteriophage 80α capsids.
A conformational switch involved in maturation of Staphylococcus aureus bacteriophage 80α capsids.
复制标题
参与金黄色葡萄球菌噬菌体 80α 衣壳成熟的构象转换。
DOI：
10.1016/j.jmb.2010.11.047
复制
发表时间：
2011
影响因子：
5.6
通讯作者：
Dokland,Terje
中科院分区：
文献类型：
--
作者：
Spilman,MichaelS;Dearborn,AltairaD;Chang,JennyR;Damle,PriyadarshanK;Christie,GailE;Dokland,Terje
噬菌体参与金黄色葡萄球菌毒力因子的传播和建立的许多方面，包括金黄色葡萄球菌致病岛（SaPI）的遗传元件的动员，其携带超抗原毒素和其他毒力因子的基因。使用辅助噬菌体提供的蛋白质将 SaPI 包装成噬菌体样转导颗粒。我们使用冷冻电子显微镜和二十面体重建来确定 80α 的原衣壳和成熟衣壳的结构，80α 是一种可以动员几种不同 SaPI 的噬菌体。 80α 衣壳具有 T=7 二十面体对称性，衣壳蛋白组织成五聚体和六聚体簇，通过显着的三聚体密度相互作用。 80α 衣壳蛋白是根据噬菌体 HK97 的衣壳蛋白折叠建模的，并拟合到 80α 重建中。模型表明，三价相互作用主要由称为 P 环的 22 残基 β 发夹结构介导，而 HK97 中未发现这种结构。衣壳扩张与在整个亚基中传播的脊柱螺旋中的构象转换相关，这与噬菌体 HK97 或 P22 中的结构域旋转机制不同。
Bacteriophages are involved in many aspects of the spread and establishment of virulence factors in Staphylococcus aureus, including the mobilization of genetic elements known as S. aureus pathogenicity islands (SaPIs), which carry genes for superantigen toxins and other virulence factors. SaPIs are packaged into phage-like transducing particles using proteins supplied by the helper phage. We have used cryo-electron microscopy and icosahedral reconstruction to determine the structures of the procapsid and the mature capsid of 80α, a bacteriophage that can mobilize several different SaPIs. The 80α capsid has T=7 icosahedral symmetry with the capsid protein organized into pentameric and hexameric clusters that interact via prominent trimeric densities. The 80α capsid protein was modeled based on the capsid protein fold of bacteriophage HK97 and fitted into the 80α reconstructions. The models show that the trivalent interactions are mediated primarily by a 22-residue β hairpin structure called the P loop that is not found in HK97. Capsid expansion is associated with a conformational switch in the spine helix that is propagated throughout the subunit, unlike the domain rotation mechanism in phage HK97 or P22.