title: Mechanisms of DNA Packaging by Large Double-Stranded DNA Viruses.
abstract: Translocation of viral double-stranded DNA (dsDNA) into the icosahedral prohead shell is catalyzed by TerL, a motor protein that has ATPase, endonuclease, and translocase activities. TerL, following endonucleolytic cleavage of immature viral DNA concatemer recognized by TerS, assembles into a pentameric ring motor on the prohead's portal vertex and uses ATP hydrolysis energy for DNA translocation. TerL's N-terminal ATPase is connected by a hinge to the C-terminal endonuclease. Inchworm models propose that modest domain motions accompanying ATP hydrolysis are amplified, through changes in electrostatic interactions, into larger movements of the C-terminal domain bound to DNA. In phage ϕ29, four of the five TerL subunits sequentially hydrolyze ATP, each powering translocation of 2.5 bp. After one viral genome is encapsidated, the internal pressure signals termination of packaging and ejection of the motor. Current focus is on the structures of packaging complexes and the dynamics of TerL during DNA packaging, endonuclease regulation, and motor mechanics.
authors.affiliation: Department of Biology, The Catholic University of America, Washington, DC 20064; email: rao@cua.edu.
authors.forename: Venigalla B
authors.initials: VB
authors.lastname: Rao
authors.affiliation: Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242; email: michael-feiss@uiowa.edu.
authors.forename: Michael
authors.initials: M
authors.lastname: Feiss
mesh_terms: D042003:DNA Packaging; D004267:DNA Viruses / Q000235:genetics* / Q000502:physiology; D004279:DNA, Viral / Q000235:genetics* / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D004279:DNA, Viral; D014764:Viral Proteins
keywords: ATPase; DNA packaging; bacteriophage; molecular motor; terminase; virus assembly