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：1975
卷号：72
期号：11
页码：4275-4279
DOI：10.1073/pnas.72.11.4275
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Treatment of a homogeneous sample of circular DNA molecules that contain at least one single-strand scission per molecule with ligase yields a population of covalently closed circles heterogeneous in the topological winding number alpha. Under proper conditions, the product molecules with different values of alpha can all be resolved by gel electrophoresis. The distributions in alpha for several DNAs, covalently closed at different temperatures, have been determined and the results have been interpreted in terms of thermal fluctuations of the DNA helix.
