title: Characterization of the initial steps in the T7 DNA ejection process.
abstract: A specialized complex, the tail, is the most common strategy employed by bacterial viruses to deliver their genome without disrupting cell integrity. T7 has a short, non-contractile tail formed by a tubular structure surrounded by fibers. Recent studies showed that incubation of the virus withEscherichia colilipopolysaccharides (LPS) resulted in complete delivery of the viral genome, demonstrating for the first time that LPS are the T7 receptor. Further screening of the bacterial envelope for proteinaceous compounds that affect T7 ejection showed that porins OmpA and OmpF affect viral particle adsorption and infection kinetics, suggesting that these proteins play a role in the first steps of virus-host interaction. Comparison of the structures before and after ejection showed the conformational changes needed in the tail for genome delivery. Structural similarities between T7 and other viruses belonging to thePodoviridaefamily suggests that they could also follow a similar DNA ejection mechanism.
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain.
authors.forename: Verónica A
authors.initials: VA
authors.lastname: González-García
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain ; Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia) ; Cantoblanco , Madrid, Spain.
authors.forename: Rebeca
authors.initials: R
authors.lastname: Bocanegra
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain.
authors.forename: Mar
authors.initials: M
authors.lastname: Pulido-Cid
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain.
authors.forename: Jaime
authors.initials: J
authors.lastname: Martín-Benito
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Cuervo
authors.affiliation: Structure of Macromolecules Department; Centro Nacional de Biotecnología; Consejo Superior de Investigaciones Científicas ; Cantoblanco , Madrid, Spain ; Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA Nanociencia) ; Cantoblanco , Madrid, Spain.
authors.forename: José L
authors.initials: JL
authors.lastname: Carrascosa
keywords: DNA ejection; Podoviridae; cryo-electron m; protein structure; tail complex