Structural changes in a marine podovirus associated with release of its genome into Prochlorococcus.
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.
Liu
Xiangan
X
National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry & Molecular Biology, Baylor College of Medicine, Houston, Texas, USA.
Zhang
Qinfen
Q
Murata
Kazuyoshi
K
Baker
Matthew L
ML
Sullivan
Matthew B
MB
Fu
Caroline
C
Dougherty
Matthew T
MT
Schmid
Michael F
MF
Osburne
Marcia S
MS
Chisholm
Sallie W
SW
Chiu
Wah
W
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
D014764:Viral Proteins