Radman-Livaja Marta, Shaw Christine, Azaro Marco, Biswas Tapan, Ellenberger Tom, Landy Arthur
Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Box G-J360, Providence, RI 02912, USA.
Mol Cell. 2003 Mar;11(3):783-94. doi: 10.1016/s1097-2765(03)00111-4.
lambda integrase (Int) mediates recombination between attachment sites on lambda phage and E. coli DNAs. With the assistance of accessory proteins that induce DNA loops, Int bridges pairs of distinct arm- and core-type DNA binding sites to form synapsed recombination complexes, which then recombine via a Holliday junction (HJ) intermediate. We show that, in addition to promoting the proper positioning of Int protomers, the arm sequences facilitate the catalytic activities of the Int tetramer, independent of accessory proteins or physical continuity between the arm and core sites. We have determined the architecture of ternary complexes containing a HJ, Int, and P'1,2 arm-type DNA. These structures accommodate simultaneous binding of Int to direct-repeat arm sites and indirect-repeat core sites and afford a new view of the higher-order recombinogenic complexes.
λ整合酶（Int）介导λ噬菌体与大肠杆菌DNA上附着位点之间的重组。在诱导DNA环的辅助蛋白的帮助下，Int将不同的臂型和核心型DNA结合位点对连接起来，形成突触状重组复合物，然后通过霍利迪连接体（HJ）中间体进行重组。我们发现，除了促进Int原聚体的正确定位外，臂序列还能促进Int四聚体的催化活性，这与辅助蛋白无关，也与臂位点和核心位点之间的物理连续性无关。我们已经确定了包含HJ、Int和P'1,2臂型DNA的三元复合物的结构。这些结构能够容纳Int同时与同向重复臂位点和反向重复核心位点结合，并为高阶重组复合物提供了新的视角。
