title: Bacillus subtilis bacteriophage SPP1 DNA packaging motor requires terminase and portal proteins.
abstract: Initiation of headful packaging of SPP1 DNA concatemers involves the interaction of the terminase, G1P and G2P, and the portal protein, G6P. G1P, which specifically recognizes the non-adjacent pacL and pacR subsites and directs loading of G2P to pacC, interacts with G6P. G2P, which has endonuclease, DNA binding, and ATPase activities, interacts with G1P and does it transiently with G6P. The stoichiometry of G1P on the G1P.G2P complex promotes the transition from a G2P endonuclease to an ATPase. G6P does not alter the endonuclease activity of G2P. Both G1P and G6P, which do not have endogenous ATPase activity, synergistically enhance and modulate the ATPase activity of G2P. Based on these results, we propose a model in which the modulation of the ATPase and endonuclease activities of G2P accounts for the role of the terminase in headful packaging.
authors.affiliation: Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
authors.forename: Ana G
authors.initials: AG
authors.lastname: Camacho
authors.forename: Aranzazu
authors.initials: A
authors.lastname: Gual
authors.forename: Rudi
authors.initials: R
authors.lastname: Lurz
authors.forename: Paulo
authors.initials: P
authors.lastname: Tavares
authors.forename: Juan C
authors.initials: JC
authors.lastname: Alonso
mesh_terms: D001412:Bacillus subtilis / Q000821:virology*; D001435:Bacteriophages / Q000201:enzymology*; D004279:DNA, Viral / Q000737:chemistry / Q000378:metabolism*; D004706:Endodeoxyribonucleases / Q000737:chemistry / Q000378:metabolism*; D005990:Glycerol / Q000494:pharmacology; D007700:Kinetics; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000821:virology; D011485:Protein Binding; D011487:Protein Conformation; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*; D054334:Viral Regulatory and Accessory Proteins / Q000737:chemistry / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D004279:DNA, Viral; D020409:Molecular Motor Proteins; D014764:Viral Proteins; D054334:Viral Regulatory and Accessory Proteins; C115880:portal protein, Bacteriophage SPP1; C073671:SPP1 pac region protein, Bacteriophage SPP1; D004706:Endodeoxyribonucleases; C030894:terminase; D005990:Glycerol