Conformational isomerization in phage Mu transpososome assembly: effects of the transpositional enhancer and of MuB.
Conformational isomerization in phage Mu transpososome assembly: effects of the transpositional enhancer and of MuB.
复制标题
噬菌体 Mu 转座体组装中的构象异构化：转座增强子和 MuB 的作用。
DOI：
10.1093/emboj/20.23.6927
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发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Mizuuchi,K
中科院分区：
文献类型：
--
作者：
Mizuuchi,M;Mizuuchi,K
噬菌体 Mu DNA 转座的启动需要组装称为 Mu 转座体的高级蛋白质-DNA 复合物，其中包含两个 Mu DNA 末端和 MuA 转座酶四聚体。 Mu 转座体组装受到高度调控，涉及转座酶结合的多个 DNA 位点，包括称为内部激活序列 (IAS) 的转座增强子。此外，许多蛋白质辅助因子也参与其中，包括靶 DNA 激活剂 MuB ATP 酶。我们研究了组装辅因子对转座体组装动力学的影响，目的是破译受辅因子影响的反应步骤。转座增强子 IAS 似乎对 MuA 结合的两个 Mu 末端片段的初始配对影响不大。相反，它加速了将可逆复合体转化为稳定转座体的突触后构象步骤。 MuB 的转座体组装刺激不需要其稳定的 DNA 结合活性，这对于将转座引导至远离供体转座子的位点似乎至关重要。
Initiation of phage Mu DNA transposition requires assembly of higher order protein–DNA complexes called Mu transpososomes containing the two Mu DNA ends and MuA transposase tetramer. Mu transpososome assembly is highly regulated and involves multiple DNA sites for transposase binding, including a transpositional enhancer called the internal activation sequence (IAS). In addition, a number of protein cofactors participate, including the target DNA activator MuB ATPase. We investigated the impact of the assembly cofactors on the kinetics of transpososome assembly with the aim of deciphering the reaction steps that are influenced by the cofactors. The transpositional enhancer IAS appears to have little impact on the initial pairing of the two Mu end segments bound by MuA. Instead, it accelerates the post‐synaptic conformational step (s) that converts the reversible complex to the stable transpososome. The transpososome assembly stimulation by MuB does not require its stable DNA binding activity, which appears critical for directing transposition to sites distant from the donor transposon.