德国马尔堡大学Martin Thanbichler、Gert Bange等研究人员合作发现，ParB型DNA分离蛋白是CTP依赖的分子开关。该研究于2019年12月12日发表于国际一流学术期刊《细胞》。

研究人员报告了一个ParB样蛋白（PadC）的晶体结构，该晶体结构与核糖核苷酸CTP紧密结合。PadC的CTP结合袋在ParB中保守，并由已知对ParB功能必不可少的特征膜体组成。研究人员发现，ParB确实与CTP相互作用，并且需要核苷酸结合才能在体内进行DNA压缩。研究人员进一步表明，CTP结合调节ParB对着丝粒parS位点的亲和力，而parS识别则激活其CTPase活性。因此，ParB蛋白是一类新的CTP依赖性分子开关，它们与ATPase和GTPases协同作用以控制基本的细胞功能。

据悉，在细胞分裂过程中，新复制的DNA被主动分离到子细胞中。在大多数细菌中，该过程涉及DNA结合蛋白ParB，该蛋白将姐妹DNA分子的着丝粒区域浓缩成动粒状结构，从而募集DNA分区ATPase ParA和原核SMC/condensin复合物。

附：英文原文

Title: ParB-type DNA Segregation Proteins Are CTP-Dependent Molecular Switches

Author: Manuel Osorio-Valeriano, Florian Altegoer, Wieland Steinchen, Svenja Urban, Ying Liu, Gert Bange, Martin Thanbichler

Issue&Volume: 2019/12/12

Abstract: During cell division, newly replicated DNA is actively segregated to the daughtercells. In most bacteria, this process involves the DNA-binding protein ParB, whichcondenses the centromeric regions of sister DNA molecules into kinetochore-like structuresthat recruit the DNA partition ATPase ParA and the prokaroytic SMC/condensin complex.Here, we report the crystal structure of a ParB-like protein (PadC) that emerges totightly bind the ribonucleotide CTP. The CTP-binding pocket of PadC is conserved inParB and composed of signature motifs known to be essential for ParB function. Wefind that ParB indeed interacts with CTP and requires nucleotide binding for DNA condensationin vivo. We further show that CTP-binding modulates the affinity of ParB for centromericparS sites, whereas parS recognition stimulates its CTPase activity. ParB proteins thus emerge as a new classof CTP-dependent molecular switches that act in concert with ATPases and GTPases tocontrol fundamental cellular functions.

DOI: 10.1016/j.cell.2019.11.015

Source: https://www.cell.com/cell/fulltext/S0092-8674(19)31271-1