Baker T A, Mizuuchi M, Savilahti H, Mizuuchi K
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases National Institutes of Health, Bethesda, Maryland 20892.
Cell. 1993 Aug 27;74(4):723-33. doi: 10.1016/0092-8674(93)90519-v.
A single tetramer of Mu transposase (MuA) pairs the recombination sites, cleaves the donor DNA, and joins these ends to a target DNA by strand transfer. Analysis of C-terminal deletion derivatives of MuA reveals that a 30 amino acid region between residues 575 and 605 is critical for these three steps. Although inactive on its own, a deletion protein lacking this region assembles with the wild-type protein. These mixed tetramers carry out donor cleavage but do not promote strand transfer, even when the donor cleavage stage is bypassed. These data suggest that the active center of the transposase is composed of the C-terminus of four MuA monomers; one dimer carries out donor cleavage while all four monomers contribute to strand transfer.
Mu转座酶（MuA）的单个四聚体将重组位点配对，切割供体DNA，并通过链转移将这些末端连接到目标DNA上。对MuA的C端缺失衍生物的分析表明，575至605位残基之间的30个氨基酸区域对这三个步骤至关重要。尽管该区域自身无活性，但缺乏此区域的缺失蛋白可与野生型蛋白组装。这些混合四聚体可进行供体切割，但即使绕过供体切割阶段也不促进链转移。这些数据表明，转座酶的活性中心由四个MuA单体的C端组成；一个二聚体进行供体切割，而所有四个单体都参与链转移。
