title: Defining molecular and domain boundaries in the bacteriophage phi29 DNA packaging motor.
abstract: Cryo-electron microscopy (cryo-EM) studies of the bacteriophage phi29 DNA packaging motor have delineated the relative positions and molecular boundaries of the 12-fold symmetric head-tail connector, the 5-fold symmetric prohead RNA (pRNA), the ATPase that provides the energy for packaging, and the procapsid. Reconstructions, assuming 5-fold symmetry, were determined for proheads with 174-base, 120-base, and 71-base pRNA; proheads lacking pRNA; proheads with ATPase bound; and proheads in which the packaging motor was missing the connector. These structures are consistent with pRNA and ATPase forming a pentameric motor component around the unique vertex of proheads. They suggest an assembly pathway for the packaging motor and a mechanism for DNA translocation into empty proheads.
authors.affiliation: Department of Biochemistry and Molecular Biology, 301 University Boulevard, University of Texas Medical Branch, Galveston, TX 77555-0647, USA.
authors.forename: Marc C
authors.initials: MC
authors.lastname: Morais
authors.forename: Jaya S
authors.initials: JS
authors.lastname: Koti
authors.forename: Valorie D
authors.initials: VD
authors.lastname: Bowman
authors.forename: Emilio
authors.initials: E
authors.lastname: Reyes-Aldrete
authors.forename: Dwight L
authors.initials: DL
authors.lastname: Anderson
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D017103:Bacillus Phages / Q000737:chemistry*; D020285:Cryoelectron Microscopy; D042003:DNA Packaging; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D012322:RNA Precursors / Q000737:chemistry / Q000378:metabolism; D014764:Viral Proteins / Q000737:chemistry* / Q000378:metabolism; D019065:Virus Assembly
chemical_list: D020409:Molecular Motor Proteins; D012322:RNA Precursors; D014764:Viral Proteins