Changes in chromatin chain flexibility during condensation induced by sodium chloride, as evidenced by electric dichroism

FEBS Letters

Houssier, Claude²  Koch, Michel H.J.¹  Marquet, Roland²  Favazza, Marisa² 

[1]European Molecular Biology Laboratory, c/o DESY, Notkestrasse 85, D-2000 Hamburg 52, FRG

[2]Laboratoire de Chimie Macromoléculaire et Chimie Physique, Université de Liège, Sart-Tilman (B6), B-4000 Liège, Belgium

关键词: Chromatin;    Compaction;    Flexibility;    Electric dichroism;    FLD;    flow linear dichroism;    ELD;    electric linear dichroism;   

DOI  :  10.1016/0014-5793(90)80171-E

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The electric linear dichroism of chicken erythrocyte chromatin has been measured as a function of NaCl concentration in the 1–28 mM ionic strength range, using a specially designed Kerr cell with reduced pathlength, and thus, smaller electrode surface. This allowed the determination of the dichroism of compact chromatin in conditions where artifacts due to possible contribution from turbidity are avoided, which was not the case for previous studies in the presence of di- or multivalent cations. The linear dichroism of compact chromatin was found to be positive, as expected from models of the 30-nm fibre in which the linker DNA runs perpendicular to the fibre axis. The dependence of the relaxation times on ionic strength reveals that the process of compaction is first accompanied by an increase in flexibility of the chain followed by a decrease, in the range of 5–10 mM NaCl, and a further decrease above 10 mM NaCl, corresponding to the compaction of the 30 nm fibre.

【 授权许可】

Unknown