C-terminal repetitive motifs in Vp130 present at the unique vertex of the Chlorovirus capsid are essential for binding to the host Chlorella cell wall
- 作者：Hideki Onimatsu ; Kei Suganuma ; Shushi Uenoyama and Takashi Yamada
- 关键词：Chlorovirus ; Cell wall binding protein ; Vp130 ; C-terminal repetitive motif ; Unique vertex
- 刊名：Virology
- 出版年：2006
- 期刊代码：108_00426822
- 类别：imm
- 出版时间：30 September 2006
- 卷：353
- 期：2
- 页码：433-442
- 文件大小：1146 K
摘要
Previously, Vp130, a chloroviral structural protein, was found to have host-cell-wall-binding activity for NC64A-viruses (PBCV-1 and CVK2). In this study, we have isolated and characterized the corresponding protein from chlorovirus CVGW1, one of Pbi-viruses that have a different host range. In NC64A-viruses, Vp130 consists of a highly conserved N-terminal domain, internal repeats of 70–73 aa motifs and a C-terminal domain occupied by 23–26 tandem repeats of a PAPK motif. However, CVGW1 was found to have a slightly different Vp130 construction where the PAPK repeats were not in the C-terminus but internal. Immunofluorescence microscopy with a specific antibody revealed that the C-terminal region containing the Vp130 repetitive motifs from PBCV-1 and CVK2 was responsible for binding to Chlorella cell walls. Furthermore, by immunoelectron microscopy and immunofluorescence microscopy, Vp130 was localized at a unique vertex of the chlorovirus particle and was found to be masked through binding to the host cells. These results suggested that Vp130 is localized at a unique vertex on the virion, with the C-terminal repetitive units outside for cell wall binding.