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solenoid
There are 5 levels of folding of DNA in eukaryotic chromosomes. The solenoid represents the 2nd level of DNA folding. Nucleosomes (1st level of folding) are organized into solenoids which form the 30 nm fiber seen in the electron microscope. There are 12 nucleosomes in a solenoid [2] & each full turn of the solenoid accounts for 1.2 kb of DNA. The solenoids in turn are folded into loops (3rd level of folding), which form attachment sites to the nuclear matrix at their base.
General
DNA motif
macromolecular complex
Figures/Diagrams
solenoid
Properties
SIZE: entity length = 1.2 KB/TURN
WIDTH = 30 NM
COMPARTMENT: cell nucleus
References
- Manuelidis L.
A view of interphase chromosomes.
Science. 1990 Dec 14;250(4987):1533-40. Review.
PMID: 2274784
- Filipski J, Leblanc J, Youdale T, Sikorska M, Walker PR.
Periodicity of DNA folding in higher order chromatin structures.
EMBO J. 1990 Apr;9(4):1319-27.
PMID: 2323342
Component-of
chromosomal-loop
Components
linker-DNA
nucleosome