title: Structural changes in a marine podovirus associated with release of its genome into Prochlorococcus.
abstract: Podovirus P-SSP7 infects Prochlorococcus marinus, the most abundant oceanic photosynthetic microorganism. Single-particle cryo-electron microscopy yields icosahedral and asymmetrical structures of infectious P-SSP7 with 4.6-A and 9-A resolution, respectively. The asymmetric reconstruction reveals how symmetry mismatches are accommodated among five of the gene products at the portal vertex. Reconstructions of infectious and empty particles show a conformational change of the 'valve' density in the nozzle, an orientation difference in the tail fibers, a disordering of the C terminus of the portal protein and the disappearance of the core proteins. In addition, cryo-electron tomography of P-SSP7 infecting Prochlorococcus showed the same tail-fiber conformation as that in empty particles. Our observations suggest a mechanism whereby, upon binding to the host cell, the tail fibers induce a cascade of structural alterations of the portal vertex complex that triggers DNA release.
authors.affiliation: National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry & Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.
authors.forename: Xiangan
authors.initials: X
authors.lastname: Liu
authors.forename: Qinfen
authors.initials: Q
authors.lastname: Zhang
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Murata
authors.forename: Matthew L
authors.initials: ML
authors.lastname: Baker
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Sullivan
authors.forename: Caroline
authors.initials: C
authors.lastname: Fu
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Dougherty
authors.forename: Michael F
authors.initials: MF
authors.lastname: Schmid
authors.forename: Marcia S
authors.initials: MS
authors.lastname: Osburne
authors.forename: Sallie W
authors.initials: SW
authors.lastname: Chisholm
authors.forename: Wah
authors.initials: W
authors.lastname: Chiu
mesh_terms: D002213:Capsid / Q000737:chemistry* / Q000378:metabolism; D016679:Genome, Viral; D008958:Models, Molecular; D017902:Podoviridae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D048929:Prochlorococcus / Q000821:virology*; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism; D014771:Virion / Q000737:chemistry
chemical_list: D014764:Viral Proteins