title: Filamentous bacteriophage contract into hollow spherical particles upon exposure to a chloroform-water interface.
abstract: The bacteriophage M13 is a 1 micrometer long filament consisting of a circular single-stranded DNA loop firmly held within a tubular protein and capsid. We report here that exposure to a chloroform-water interface initiates a 20 fold contraction of each filament into a hollow protein sphere. In these 0.04 micrometer diameter particles, termed M13 "spheroids," two thirds of the DNA is apparently extruded through a hole in the wall of the spheroid; the portion of DNA remaining inside the shell centers about the origins of M13 DNA replication. These results suggest that the filament, upon exposure to a membrane environment, undergoes an ordered change whereby the DNA is released into the cell and the coat protein is changed to a form more easily solubilized by the membrane lipids.
mesh_terms: D001665:Binding Sites; D002725:Chloroform / Q000494:pharmacology*; D003090:Coliphages / Q000187:drug effects* / Q000648:ultrastructure; D004279:DNA, Viral; D008563:Membrane Lipids / Q000494:pharmacology; D008854:Microscopy, Electron; D008954:Models, Biological; D009690:Nucleic Acid Conformation / Q000187:drug effects; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication
chemical_list: D004279:DNA, Viral; D008563:Membrane Lipids; D014764:Viral Proteins; D002725:Chloroform