文章基本信息

标题：How many base-pairs per turn does DNA have in solution and in chromatin? Some theoretical calculations
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作者：M Levitt
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：2
页码：640-644
DOI：10.1073/pnas.75.2.640
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Calculations on a 20-base pair segment of DNA double helix using empirical energy functions show that DNA can be bent smoothly and uniformly into a superhelix with a small enough radius (45 A) to fit the dimensions of chromatin. The variation of energy with the twist of the base pairs about the helix axis shows the straight DNA free in solution is most stable with about 10 1/2 base pairs per turn rather than 10 as observed in the solid state, whereas superhelical DNA in chromatin is most stable with about 10 base pairs per turn. This result, which has a simple physical interpretation, explains the pattern of nuclease cuts and the linkage number changes observed for DNA arranged in chromatin.