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

Virology. 2006 Sep 30;353(2):433-42. doi: 10.1016/j.virol.2006.06.010. Epub 2006 Jul 25.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Cell Wall / virology
  • Chlorella / virology*
  • Genes, Viral
  • Ireland
  • Molecular Sequence Data
  • Phycodnaviridae / chemistry*
  • Phycodnaviridae / isolation & purification
  • Phycodnaviridae / physiology
  • Protein Structure, Tertiary / physiology
  • Sequence Alignment
  • Species Specificity
  • Structure-Activity Relationship
  • Viral Envelope Proteins / chemistry*
  • Viral Envelope Proteins / physiology
  • Virion / chemistry
  • Virus Replication

Substances

  • Viral Envelope Proteins