Nucleic Acids Research, 1980, Vol. 8, No. 20 4803-4820
© 1980
MOLECULAR BIOLOGY |
DNA wrapping in nucleosomes. The linking number problem re-examined
Department of Biological Sciences, Purdue University West Lafayette, IN 47907, USA
Received July 21, 1980. Chromatin was assembled in vitro from relaxed closed circular DNA (SV40) and core histones at histone to DNA ratios of 0.2 to 0.3 (g/g) and incubated with topoisomerase I to relax supercoils in DNA regions not constrained by protein. Addition of histones H1 + H5 to the chromatin at an ionic strength of 0.1 M, in the presence of the solubilizing agent, polyglutamic acid, and topoisomerase I, increased the magnitude of the DNA linking number change, relative to protein-free DNA. No change in the linking number distrthution occurred for relaxed protein-free DNA under these conditions. Control experiments indicated that the increase in the absolute value of the DNA linking number change in the chromatin could not be attributed to an increase in the number of nucleosomes per DNA molecule. These data suggest a solution to the linking number problem associated with models of chromatin structure.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
M. Ivanchenko, A. Hassan, K. van Holde, and J. Zlatanova H1 Binding Unwinds DNA. EVIDENCE FROM TOPOLOGICAL ASSAYS J. Biol. Chem., December 20, 1996; 271(51): 32580 - 32585. [Abstract] [Full Text] [PDF] |
||||
