Molecular architecture of the DNA-binding sites of the P-loop MipZ and ParA from Caulobacter crescentus
Molecular architecture of the DNA-binding sites of the P-loop MipZ and ParA from Caulobacter crescentus
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DOI：
10.1093/nar/gkaa192
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发表时间：
2020-05-21
影响因子：
14.9
通讯作者：
Thanbichler, Martin
中科院分区：
文献类型：
--
作者：
Corrales-Guerrero, Laura;He, Binbin;Thanbichler, Martin
新月茎杆菌的染色体分离和细胞分裂的时空调控是由两种不同的p环atp酶ParA和MipZ介导的。这两种蛋白质形成动态浓度梯度，控制细胞内调节靶标的定位。它们的正确定位取决于它们在单体和二聚体状态之间的核苷酸依赖循环，以及二聚体与类核结合的能力。在这项研究中，我们采用遗传筛选、生化分析和氢/氘交换质谱相结合的方法，全面绘制了介导MipZ和ParA与DNA相互作用的残基。我们发现，MipZ具有非特异性的dna结合活性，这种活性依赖于二聚体界面两侧的一组带正电和疏水残基。将我们的分析扩展到ParA，我们发现MipZ和ParA的DNA结合位点在组成上明显不同，尽管它们在二聚体表面的相对位置和它们的DNA结合模式是保守的。与先前的实验工作一致，生物信息学分析表明，相同的原理可能适用于P-loop atp酶家族的其他成员。因此，p环atp酶具有共同的机制特征，尽管它们的功能在进化过程中有相当大的差异。
The spatiotemporal regulation of chromosome segregation and cell division in Caulobacter crescentus is mediated by two different P-loop ATPases, ParA and MipZ. Both of these proteins form dynamic concentration gradients that control the positioning of regulatory targets within the cell. Their proper localization depends on their nucleotide-dependent cycling between a monomeric and a dimeric state and on the ability of the dimeric species to associate with the nucleoid. In this study, we use a combination of genetic screening, biochemical analysis and hydrogen/deuterium exchange mass spectrometry to comprehensively map the residues mediating the interactions of MipZ and ParA with DNA. We show that MipZ has non-specific DNA-binding activity that relies on an array of positively charged and hydrophobic residues lining both sides of the dimer interface. Extending our analysis to ParA, we find that the MipZ and ParA DNA-binding sites differ markedly in composition, although their relative positions on the dimer surface and their mode of DNA binding are conserved. In line with previous experimental work, bioinformatic analysis suggests that the same principles may apply to other members of the P-loop ATPase family. P-loop ATPases thus share common mechanistic features, although their functions have diverged considerably during the course of evolution.