title: Structure of toroidal DNA collapsed inside the phage capsid.
abstract: The structure of DNA toroids made of individual DNA molecules of various lengths (3,000 to 55,000 bp) was studied, by using partially filled bacteriophage capsids in conjunction with cryoelectron microscopy. The tetravalent cation spermine was diffused through the capsid to condense the DNA under conditions that were chosen to produce a hexagonal packing. Our results demonstrate that the frustration arising between chirality and hexagonal packing leads to the formation of twist walls; the correlation between helices combined with their strong curvature impose variations of the DNA helical pitch.
authors.affiliation: Laboratoire de Physique des Solides, Centre Nationale de la Recherche Scientifique, Unité Mixte de Recherche 8502, Bât 510, Université Paris-Sud XI, Centre d'Orsay, Orsay Cedex, France.
authors.forename: Amélie
authors.initials: A
authors.lastname: Leforestier
authors.forename: Françoise
authors.initials: F
authors.lastname: Livolant
mesh_terms: D001435:Bacteriophages / Q000737:chemistry* / Q000235:genetics / Q000648:ultrastructure*; D002213:Capsid / Q000737:chemistry* / Q000648:ultrastructure; D004279:DNA, Viral / Q000737:chemistry* / Q000648:ultrastructure
chemical_list: D004279:DNA, Viral