title: Structure of the bacteriophage phi29 DNA packaging motor.
abstract: Motors generating mechanical force, powered by the hydrolysis of ATP, translocate double-stranded DNA into preformed capsids (proheads) of bacterial viruses and certain animal viruses. Here we describe the motor that packages the double-stranded DNA of the Bacillus subtilis bacteriophage phi29 into a precursor capsid. We determined the structure of the head-tail connector--the central component of the phi29 DNA packaging motor--to 3.2 A resolution by means of X-ray crystallography. We then fitted the connector into the electron densities of the prohead and of the partially packaged prohead as determined using cryo-electron microscopy and image reconstruction analysis. Our results suggest that the prohead plus dodecameric connector, prohead RNA, viral ATPase and DNA comprise a rotary motor with the head-prohead RNA-ATPase complex acting as a stator, the DNA acting as a spindle, and the connector as a ball-race. The helical nature of the DNA converts the rotary action of the connector into translation of the DNA.
authors.affiliation: Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA.
authors.forename: A A
authors.initials: AA
authors.lastname: Simpson
authors.forename: Y
authors.initials: Y
authors.lastname: Tao
authors.forename: P G
authors.initials: PG
authors.lastname: Leiman
authors.forename: M O
authors.initials: MO
authors.lastname: Badasso
authors.forename: Y
authors.initials: Y
authors.lastname: He
authors.forename: P J
authors.initials: PJ
authors.lastname: Jardine
authors.forename: N H
authors.initials: NH
authors.lastname: Olson
authors.forename: M C
authors.initials: MC
authors.lastname: Morais
authors.forename: S
authors.initials: S
authors.lastname: Grimes
authors.forename: D L
authors.initials: DL
authors.lastname: Anderson
authors.forename: T S
authors.initials: TS
authors.lastname: Baker
authors.forename: M G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D000251:Adenosine Triphosphatases / Q000737:chemistry; D017103:Bacillus Phages / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D002213:Capsid / Q000737:chemistry / Q000378:metabolism; D020285:Cryoelectron Microscopy; D018360:Crystallography, X-Ray; D004279:DNA, Viral / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D020409:Molecular Motor Proteins / Q000737:chemistry* / Q000378:metabolism; D009690:Nucleic Acid Conformation; D012367:RNA, Viral / Q000737:chemistry
chemical_list: D004279:DNA, Viral; D020409:Molecular Motor Proteins; D012367:RNA, Viral; D000251:Adenosine Triphosphatases