Modulation of the viral ATPase activity by the portal protein correlates with DNA packaging efficiency.
DNA packaging in tailed bacteriophages and herpesviruses requires assembly of a complex molecular machine at a specific vertex of a preformed procapsid. As in all these viruses, the DNA translocation motor of bacteriophage SPP1 is composed of the portal protein (gp6) that provides a tunnel for DNA entry into the procapsid and of the viral ATPase (gp1-gp2 complex) that fuels DNA translocation. Here we studied the cross-talk between the components of the motor to control its ATP consumption and DNA encapsidation. We showed that gp6 embedded in the procapsid structure stimulated more than 10-fold the gp2 ATPase activity. This stimulation, which was significantly higher than the one conferred by isolated gp6, depended on the presence of gp1. Mutations in different regions of gp6 abolished or decreased the gp6-induced stimulation of the ATPase. This effect on gp2 activity was observed both in the presence and in the absence of DNA and showed a strict correlation with the efficiency of DNA packaging into procapsids containing the mutant portals. Our results demonstrated that the portal protein has an active control over the viral ATPase activity that correlates with the performance of the DNA packaging motor.
Oliveira
Leonor
L
Unité de Virologie Moléculaire et Structurale, Unité Mixte de Recherche (UMR) CNRS 2472, UMR INRA 1157 and Institut Fédératif de Recherche 115, Bâtiment 14B, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France. Electronic address: oliveira@vms.cnrs-gif.fr.
Henriques
Adriano O
AO
Laboratory for Microbial Development, Instituto de Tecnologia Química e Biológica, Apartado 127, 2781-901 Oeiras, Portugal.
Tavares
Paulo
P
Unité de Virologie Moléculaire et Structurale, Unité Mixte de Recherche (UMR) CNRS 2472, UMR INRA 1157 and Institut Fédératif de Recherche 115, Bâtiment 14B, Avenue de la Terrasse, 91198 Gif-sur-Yvette Cedex, France.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism; D001435:Bacteriophages / Q000502:physiology*; D001692:Biological Transport; D042003:DNA Packaging; D020409:Molecular Motor Proteins; D010957:Plasmids / Q000378:metabolism / Q000502:physiology*; D020239:Receptor Cross-Talk; D014764:Viral Proteins / Q000502:physiology*
D020409:Molecular Motor Proteins; D014764:Viral Proteins; C115880:portal protein, Bacteriophage SPP1; D000255:Adenosine Triphosphate; D000251:Adenosine Triphosphatases