title: Chlamydiaphage Chp2, a skeleton in the phiX174 closet: scaffolding protein and procapsid identification.
abstract: Chlamydiaphage Chp2 is a member of the family Microviridae, of which bacteriophage phiX174 is the type species. Although grouped in the same family, the relationship between the Microviridae coliphages and the Chp2-like viruses, which infect obligate intracellular parasitic bacteria, is quite distant, with major differences in structural protein content and scaffolding protein dependence. To investigate the morphogenesis of Chp2, large particles were isolated from infected Chlamydophila abortus by equilibrium and rate zonal sedimentation. A monoclonal antibody that recognizes only assembled viral coat proteins was used in these detection assays. Thus, the detected particles represent virions and/or postcapsid formation assembly intermediates. Two distinct particle types were detected, differing in both protein and DNA content. Filled particles lacked VP3, the putative internal scaffolding protein, whereas empty particles contained this protein. These results indicate that VP3 is a scaffolding protein and that the isolated VP3-containing particles most likely represent Chp2 procapsids.
authors.affiliation: Molecular Microbiology Group, University of Medical School, Southampton General Hospital, Southampton, United Kingdom.
authors.forename: Ian N
authors.initials: IN
authors.lastname: Clarke
authors.forename: Leslie T
authors.initials: LT
authors.lastname: Cutcliffe
authors.forename: J Sylvia
authors.initials: JS
authors.lastname: Everson
authors.forename: Sarah A
authors.initials: SA
authors.lastname: Garner
authors.forename: Paul R
authors.initials: PR
authors.lastname: Lambden
authors.forename: Paddy J
authors.initials: PJ
authors.lastname: Pead
authors.forename: Mark A
authors.initials: MA
authors.lastname: Pickett
authors.forename: Karie L
authors.initials: KL
authors.lastname: Brentlinger
authors.forename: Bentley A
authors.initials: BA
authors.lastname: Fane
mesh_terms: D010584:Bacteriophage phi X 174 / Q000145:classification / Q000235:genetics; D002213:Capsid; D036022:Capsid Proteins / Q000378:metabolism*; D023501:Chlamydophila / Q000821:virology*; D004279:DNA, Viral / Q000032:analysis; D008854:Microscopy, Electron; D017914:Microviridae / Q000145:classification / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D015678:Viral Structural Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014771:Virion / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D036022:Capsid Proteins; D004279:DNA, Viral; D015678:Viral Structural Proteins