文章基本信息

标题：Recombination of knotted substrates by Tn3 resolvase
本地全文：下载
作者：P Dröge ; N R Cozzarelli
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：1989
卷号：86
期号：16
页码：6062-6066
DOI：10.1073/pnas.86.16.6062
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We studied the site orientation specificity for recombination by purified Tn3 resolvase. With standard plasmid substrates, resolvase acts only on directly repeated recombination sites. Knotting, however, makes inverted site substrates equally efficient. The structure of the knotted products of recombination shows that the DNA wrapped around resolvase in the synaptic intermediate has the same local geometry as the standard substrate but is reversed in topological sign. Similarly, the same strand exchange with the two substrates generates supercoils with opposite signs. Thus, DNA geometry rather than topology is critical for these features of recombination. The knotted inverse substrate like the direct site substrate must be (-) supercoiled under standard reaction conditions. However, under conditions in which supercoiling is not required, the structure of the knotted product is apparently the same. This indicates that the unique direction of strand exchange is determined by the structure of the synaptosome and not by (-) supercoiling of the substrate.