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

Onimatsu Hideki

Suganuma Kei

Uenoyama Shushi

Yamada Takashi

Virology

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.

C-terminal repetitive motif

Cell wall binding protein

Chlorovirus

Unique vertex

Vp130

Botany [ 470 ]

eng

Elsevier Inc.

Copyright (c) 2006 Elsevier Inc.

[ISSN] 0042-6822

[DOI] 10.1016/j.virol.2006.06.010

[NCID] AA00884454

[DOI] http://dx.doi.org/10.1016/j.virol.2006.06.010 isVersionOf