title: Insight into DNA and protein transport in double-stranded DNA viruses: the structure of bacteriophage N4.
abstract: Bacteriophage N4 encapsidates a 3500-aa-long DNA-dependent RNA polymerase (vRNAP), which is injected into the host along with the N4 genome upon infection. The three-dimensional structures of wild-type and mutant N4 viruses lacking gp17, gp50, or gp65 were determined by cryoelectron microscopy. The virion has an icosahedral capsid with T=9 quasi-symmetry that encapsidates well-organized double-stranded DNA and vRNAP. The tail, attached at a unique pentameric vertex of the head, consists of a neck, 12 appendages, and six ribbons that constitute a non-contractile sheath around a central tail tube. Comparison of wild-type and mutant virus structures in conjunction with bioinformatics established the identity and virion locations of the major capsid protein (gp56), a decorating protein (gp17), the vRNAP (gp50), the tail sheath (gp65), the appendages (gp66), and the portal protein (gp59). The N4 virion organization provides insight into its assembly and suggests a mechanism for genome and vRNAP transport strategies utilized by this unique system.
authors: Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555-0647, USA.
authors: Kyung H
authors: KH
authors: Choi
authors: Jennifer
authors: J
authors: McPartland
authors: Irene
authors: I
authors: Kaganman
authors: Valorie D
authors: VD
authors: Bowman
authors: Lucia B
authors: LB
authors: Rothman-Denes
authors: Michael G
authors: MG
authors: Rossmann
mesh_terms: D025522:Bacteriophage N4 / Q000201:enzymology / Q000378:metabolism / Q000648:ultrastructure*; D020285:Cryoelectron Microscopy; D004279:DNA, Viral / Q000378:metabolism* / Q000648:ultrastructure; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D021381:Protein Transport; D014764:Viral Proteins / Q000378:metabolism*
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins; D012321:DNA-Directed RNA Polymerases