title: Structure models for DNA in filamentous viruses with phosphates near the center.
abstract: DNA structure models deduced from X-ray and physicochemical  data for Pfl, Xf, and fd viruses have two antiparallel chains wound in helices of approximately 15 A pitch with the phosphates near the structure axes and the bases directed outward. The models, which differ for each virus, are used to interpret ultraviolet absorbance and fluorescence data in terms of DNA protein interactions.
mesh_terms: D004279:DNA, Viral; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D009943:Organophosphorus Compounds; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D014961:X-Ray Diffraction
chemical_list: D004279:DNA, Viral; D009943:Organophosphorus Compounds