Franke Claudia, Matschl Urte, Bruns Michael
Heinrich-Pette-Institut für Experimentelle Virologie und Immunologie an der Universität Hamburg, Martinistrasse 52, D-20251 Hamburg, Germany.
Virology. 2007 Mar 1;359(1):126-36. doi: 10.1016/j.virol.2006.09.006. Epub 2006 Oct 12.
The large surface antigen L of duck hepatitis B virus exhibits a mixed topology with the preS domains of the protein alternatively exposed to the particles' interior or exterior. After separating virions from subviral particles (SVPs), we compared their L topologies and showed that both particle types exhibit the same amount of L with the following differences: 1--preS of intact virions was enzymatically digested with chymotrypsin, whereas in SVPs only half of preS was accessible, 2--phosphorylation of L at S118 was completely removed by phosphatase treatment only in virions, 3--iodine-125 labeling disclosed a higher ratio of exposed preS to S domains in virions compared to SVPs. These data point towards different surface architectures of virions and SVPs. Because the preS domain acts in binding to a cellular receptor of hepatocytes, our findings implicate the exclusion of SVPs as competitors for the receptor binding and entry of virions.
鸭乙型肝炎病毒的大表面抗原L呈现出一种混合拓扑结构，其蛋白的前S结构域交替暴露于病毒颗粒的内部或外部。在从亚病毒颗粒（SVP）中分离出病毒粒子后，我们比较了它们的L拓扑结构，结果表明两种颗粒类型的L含量相同，但存在以下差异：1——完整病毒粒子的前S被胰凝乳蛋白酶酶解，而在SVP中只有一半的前S可被作用；2——仅在病毒粒子中，S118位点的L磷酸化通过磷酸酶处理被完全去除；3——碘-125标记显示，与SVP相比，病毒粒子中暴露的前S与S结构域的比例更高。这些数据表明病毒粒子和SVP具有不同的表面结构。由于前S结构域在与肝细胞的细胞受体结合中起作用，我们的研究结果表明SVP被排除在作为病毒粒子受体结合和进入的竞争者之外。
