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Article Dans Une Revue Nature Structural and Molecular Biology Année : 2006

Structural plasticity of single chromatin fibers revealed by torsional manipulation.

Résumé

Magnetic tweezers were used to study the mechanical response under torsion of single nucleosome arrays reconstituted on tandem repeats of 5S positioning sequences. Regular arrays are extremely resilient and can reversibly accommodate a large amount of supercoiling without much change in length. This behavior is quantitatively described by a molecular model of the chromatin three-dimensional architecture. In this model, we assume the existence of a dynamic equilibrium between three conformations of the nucleosome, corresponding to different crossing statuses of the entry/exit DNAs (positive, null or negative, respectively). Torsional strain displaces that equilibrium, leading to an extensive reorganization of the fiber's architecture. The model explains a number of long-standing topological questions regarding DNA in chromatin and may provide the basis to better understand the dynamic binding of chromatin-associated proteins.

Dates et versions

hal-00090147 , version 1 (28-08-2006)

Identifiants

Citer

Aurélien Bancaud, Natalia Conde E Silva, Maria Barbi, Gaudeline Wagner, Jean-François Allemand, et al.. Structural plasticity of single chromatin fibers revealed by torsional manipulation.. Nature Structural and Molecular Biology, 2006, 13, pp.444-450. ⟨10.1038/nsmb1087⟩. ⟨hal-00090147⟩
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