DNA packing in chromatine, a manifestation of the Bonnet transformation.
The packing of DNA is described using the formalism of differential geometry. Winding of the DNA double helix around the histone 2-5 octamer forming a nucleosome and the condensation of the so-formed bead-on-a-string chromatine aided by histone 1 is interpreted as two consecutive isometric, i.e. Bonnet, transformations. The DNA double helix can be approximated to a helicoid which can be transformed isometrically to a catenoid, an approximation of the nucleosome. Owing to the organization of the histone octamer the extended chromatine takes a helicoidal shape allowing a second Bonnet transformation to consummate the condensation into a chromatine fibre.
Blum
Z
Z
Chemical Center, University of Lund, Sweden.
Lidin
S
S
D002843:Chromatin; D004247:DNA; D008961:Models, Structural; D009690:Nucleic Acid Conformation
D002843:Chromatin; D004247:DNA