Structure of chromatin and the linking number of DNA.
- 1 March 1981
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 78 (3) , 1461-1465
- https://doi.org/10.1073/pnas.78.3.1461
Abstract
Recent observations suggest that the basic supranucleosomal structure of chromatin is a zigzag helical ribbon with a repeat unit made of two nucleosomes connected by a relaxed spacer DNA. A remarkable feature of one particular ribbon is that it solves the apparent paradox between the number of DNA turns per nucleosome and the total linking number of a nucleosome-containing closed circular DNA molecule. We show here that the repeat unit of the proposed structure, which contains two nucleosomes with -1 3/4 DNA turns per nucleosome and one spacer crossover per repeat, contributes -2 to the linking number of closed circular DNA. Space-filling models show that the cylindrical 250-A chromatin fiber can be generated by twisting the ribbon.This publication has 42 references indexed in Scilit:
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