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2010-05-31T13:03:04Z

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[[Category:Retroelements]]
The "virion-associated protein" (VAP) encoded by many but not all caulimoviruses is essential for plant infection ([[Literature:100697|Stavolone ''et al.'' 2001]]), and can participate in the virus movement ([[Literature:100594|Stavolone ''et al.'' 2005]]). VAP contains coiled-coil motifs ([[Literature:100697|Stavolone ''et al.'' 2001]]; [[Literature:100738|Hoh ''et al.'' 2010]]) which are bundles of two or more amphipathic helices, characterized by an heptad repeat of hydrophobic and hydrophilic amino acids.

Studies based on four ''Caulimovirus'' species suggest that VAPs assemble as a tetramer ([[Literature:100697|Stavolone ''et al.'' 2001]]) and that the C-terminal region of the "Aphid transmission factor" (ATF) apparently interacts with VAP through the coiled-coil domains ([[Literature:100700|Leh ''et al.'' 1999]]). VAP has been associated with the virion ([[Literature:100700|Leh ''et al.'' 1999]]; [[Literature:100799|Schmidt ''et al.'' 1994]]) but it is not essential for genome packaging ([[Literature:100798|Kobayashi ''et al.'' 2002]]). Stavolone ''et al.'' ([[Literature:100594|2005]]) suggest that VAP is not a scaffolding protein but a late addition during the assembly process that plays a role in the virus spread process. In fact, VAP is indispensable for spreading virus infection within the host plant ([[Literature:100594|Stavolone ''et al.'' 2005]]) and may act as the arm of the virus particle anchored into the capsid shell ([[Literature:100748|Leclerc ''et al.'' 2001]]). VAP also interacts with the C-terminal coiled coil domain of "Movement protein" (MOV), which oligomerizes as a parallel trimer that interacts with the VAP N-terminal coiled coil ([[Literature:100594|Stavolone ''et al.'' 2005]]). This MOV-VAP interaction suggests that VAP is involved in virus movement ([[Literature:100594|Stavolone ''et al.'' 2005]]). The figure below shows a three-dimensional structure of the virion-associated protein p3 from the ''Caulimovirus'' CaMV, according to the work of [[Literature:100738|Hoh ''et al.'' 2010]].

<center>[[File:VAP_grande.png]]</center>
<center>'''''3D image of VAP-CaMV (PDB id:3f6n) available on [http://www.ebi.ac.uk/pdbsum/3f6n PDBSum] database'''''</center>

Virus associated protein - Revision history

imported>Gydbwiki at 13:03, 31 May 2010