title: The bacteriophage DNA packaging motor.
abstract: An ATP-powered DNA translocation machine encapsidates the viral genome in the large dsDNA bacteriophages. The essential components include the empty shell, prohead, and the packaging enzyme, terminase. During translocation, terminase is docked on the prohead's portal protein. The translocation ATPase and the concatemer-cutting endonuclease reside in terminase. Remarkably, terminases, portal proteins, and shells of tailed bacteriophages and herpes viruses show conserved features. These DNA viruses may have descended from a common ancestor. Terminase's ATPase consists of a classic nucleotide binding fold, most closely resembling that of monomeric helicases. Intriguing models have been proposed for the mechanism of dsDNA translocation, invoking ATP hydrolysis-driven conformational changes of portal or terminase powering DNA motion. Single-molecule studies show that the packaging motor is fast and powerful. Recent advances permit experiments that can critically test the packaging models. The viral genome translocation mechanism is of general interest, given the parallels between terminases, helicases, and other motor proteins.
authors.affiliation: Department of Biology, The Catholic University of America, Washington, D.C. 20064, USA. rao@cua.edu
authors.forename: Venigalla B
authors.initials: VB
authors.lastname: Rao
authors.forename: Michael
authors.initials: M
authors.lastname: Feiss
mesh_terms: D000595:Amino Acid Sequence; D001435:Bacteriophages / Q000235:genetics* / Q000502:physiology*; D042003:DNA Packaging / Q000235:genetics* / Q000502:physiology*; D004279:DNA, Viral / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008954:Models, Biological; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly / Q000235:genetics / Q000502:physiology
chemical_list: D004279:DNA, Viral; D020409:Molecular Motor Proteins; D014764:Viral Proteins