Mutations in Sensor 1 and Walker B in the bovine papillomavirus E1 initiator protein mimic the nucleotide-bound state.
Mutations in Sensor 1 and Walker B in the bovine papillomavirus E1 initiator protein mimic the nucleotide-bound state.
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牛乳头瘤病毒 E1 起始蛋白中 Sensor 1 和 Walker B 的突变模拟了核苷酸结合状态。
DOI：
10.1128/jvi.01756-09
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发表时间：
2010
影响因子：
5.4
通讯作者：
Stenlund,Arne
中科院分区：
文献类型：
--
作者：
Liu,Xiaofei;Stenlund,Arne
病毒复制启动蛋白是一种多功能蛋白，它利用ATP结合和其AAA+模块的水解来实现病毒基因组复制的多种功能。因此，这些蛋白对于理解AAA+蛋白如何执行多种ATP驱动功能具有特别的意义。基于最近的结构数据，我们对乳头瘤病毒E1启动蛋白中涉及ATP结合和水解的残基进行了全面的突变分析。11个目标残基中有10个在ATP水解方面存在缺陷，其中7个在ATP结合方面也存在缺陷。仍然可以结合核苷酸的三个突变体分别是Walker B基序（D478和D479）和Sensor 1 (N523)，这三个残基彼此非常接近，通常被认为参与ATP水解。然而，令人惊讶的是，这些突变体中的两个，D478A和N523A，模仿核苷酸结合状态，并且能够在没有核苷酸的情况下结合DNA。然而，在缺乏核苷酸的情况下，这些突变体不能形成E1双三聚体，这表明E1结合ATP有两种性质不同的后果，一种可以被D478A和N523A模仿，另一种不能。
Viral replication initiator proteins are multifunctional proteins that utilize ATP binding and hydrolysis by their AAA+ modules for multiple functions in the replication of their viral genomes. These proteins are therefore of particular interest for understanding how AAA+ proteins carry out multiple ATP driven functions. We have performed a comprehensive mutational analysis of the residues involved in ATP binding and hydrolysis in the papillomavirus E1 initiator protein based on the recent structural data. Ten of the eleven residues that were targeted were defective for ATP hydrolysis, and seven of these were also defective for ATP binding. The three mutants that could still bind nucleotide represent the Walker B motif (D478 and D479) and Sensor 1 (N523), three residues that are in close proximity to each other and generally are considered to be involved in ATP hydrolysis. Surprisingly, however, two of these mutants, D478A and N523A, mimicked the nucleotide bound state and were capable of binding DNA in the absence of nucleotide. However, these mutants could not form the E1 double trimer in the absence of nucleotide, demonstrating that there are two qualitatively different consequences of ATP binding by E1, one that can be mimicked by D478A and N523A and one which cannot.