title: New insights in the ϕ29 terminal protein DNA-binding and host nucleoid localization functions.
abstract: Protein-primed DNA replication constitutes a strategy to initiate viral DNA synthesis in a variety of prokaryotic and eukaryotic organisms. Although the main function of viral terminal proteins (TPs) is to provide a free hydroxyl group to start initiation of DNA replication, there are compelling evidences that TPs can also play other biological roles. In the case of Bacillus subtilis bacteriophage ϕ29, the N-terminal domain of the TP organizes viral DNA replication at the bacterial nucleoid being essential for an efficient phage DNA replication, and it contains a nuclear localization signal (NLS) that is functional in eukaryotes. Here we provide information about the structural properties of the ϕ29 TP N-terminal domain, which possesses sequence-independent DNA-binding capacity, and dissect the amino acid residues important for its biological function. By mutating all the basic residues of the TP N-terminal domain we identify the amino acids responsible for its interaction with the B. subtilis genome, establishing a correlation between the capacity of DNA-binding and nucleoid localization of the protein. Significantly, these residues are important to recruit the DNA polymerase at the bacterial nucleoid and, subsequently, for an efficient phage DNA replication.
authors.affiliation: Instituto de Biología Molecular 'Eladio Viñuela' (Consejo Superior de Investigaciones Científicas), Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid), Universidad Autónoma, Cantoblanco, 28049, Madrid, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Holguera
authors.forename: Modesto
authors.initials: M
authors.lastname: Redrejo-Rodríguez
authors.forename: Margarita
authors.initials: M
authors.lastname: Salas
authors.forename: Daniel
authors.initials: D
authors.lastname: Muñoz-Espín
mesh_terms: D017103:Bacillus Phages / Q000235:genetics / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D002942:Circular Dichroism; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism; D008958:Models, Molecular; D019913:Nuclear Localization Signals / Q000378:metabolism*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral; D019913:Nuclear Localization Signals; D014764:Viral Proteins; C040784:terminal protein, Bacillus phage phi29; D004259:DNA-Directed DNA Polymerase