Giacherio D, Hager L P
J Biol Chem. 1980 Oct 10;255(19):8963-6.
The incubation of highly purified large T antigen with relaxed, circular SV40 DNA in the presence of topoisomerase I (nicking closing enzyme) resulted in the introduction of negative superhelical turns in the DNA. ATP was not required for this reaction. A similar introduction of superhelical turns could also be obtained when a recombinant plasmid DNA (Y182), which contains sequences from both SV40 DNA and pBR322, was used. However, no effect was observed when relaxed pBR322 DNA, which does not contain SV40 DNA sequences, was incubated with T antigen in the presence of topoisomerase. These results are consistent with the hypothesis that large T antigen can recognize and unwind specific sequences on SV40 DNA.
在拓扑异构酶I（切口封闭酶）存在的情况下，将高度纯化的大T抗原与松弛的环状SV40 DNA一起温育，导致DNA中引入负超螺旋圈。该反应不需要ATP。当使用包含SV40 DNA和pBR322序列的重组质粒DNA（Y182）时，也可获得类似的超螺旋圈引入。然而，当不包含SV40 DNA序列的松弛pBR322 DNA在拓扑异构酶存在下与T抗原一起温育时，未观察到任何影响。这些结果与大T抗原可以识别并解开SV40 DNA上特定序列的假说一致。
