Scatter analysis of discrete-sized chromatin fragments favours a cylindrical organization.

TitleScatter analysis of discrete-sized chromatin fragments favours a cylindrical organization.
Publication TypeJournal Article
Year of Publication1985
AuthorsLasters, I., L. Wyns, S. Muyldermans, J. P. Baldwin, G. A. Poland, and C. Nave
JournalEur J Biochem
Volume151
Issue2
Pagination283-9
Date Published1985 Sep 2
ISSN0014-2956
KeywordsAnimals, Chemical Phenomena, Chemistry, Chickens, Chromatin, Erythrocytes, Mathematics, Neutrons, Nucleosomes, Particle Size, Peptide Fragments, Protein Conformation, Scattering, Radiation, X-Rays
Abstract

Fragments of chromatin containing 23 +/- 2.5 nucleosomes have been fractionated after light nuclease treatment of chicken erythrocyte nuclei. Low-angle scattering measures the total z-average radius of gyration of the already well-defined particles and the shape of scatter curves can be compared with three-dimensional analysis as opposed to cross-section analysis of long chromatin fragments. The data show that the particles are not spherical, have no detectable hole in the center of the structure and are best represented by a solid rod-like shape such as that generated by a coil of nucleosomes with the centre perhaps filled with linker DNA and histone H1/H5. 23 nucleosome fragments, where the DNA is partially fragmented, have near-identical scatter curves to the above-defined intact particles, indicating the primary importance of histone proteins in maintaining the integrity of the chromatin higher-order structure. Neutron scattering shows the radii of gyration to be contrast-independent, which fits in with the model calculations for solenoids. Particles with fragmented DNA and the intact particles, therefore, behave as sections of a solenoidal higher-order structure and possibly are observed as "superbeads' only during the folding and unfolding pathways of nucleosome multimers.

Alternate JournalEur. J. Biochem.
PubMed ID4029135