Abstract 1346: Structures of SegA and SegB proteins insights into chromosome segregation in archaea
Abstract 1346: Structures of SegA and SegB proteins insights into chromosome segregation in archaea
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摘要 1346：SegA 和 SegB 蛋白的结构深入了解古细菌染色体分离
DOI：
10.1016/j.jbc.2023.104006
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发表时间：
2023
影响因子：
4.8
通讯作者：
Hsiao C
中科院分区：
文献类型：
--
作者：
Hsiao C
基因组分离是所有生物体的重要过程。在生命的第三个领域——古细菌中，染色体的划分仍然很模糊。在这里，我们研究了硫磺硫化叶菌的 SegAB 系统。 SegA 是一种 ParA Walker 型 ATP 酶，SegB 是一种位点特异性 DNA 结合蛋白。我们确定了这两种蛋白质以及 SegA-DNA 和 SegB-DNA 复合物的结构 [1]。 SegA 结构揭示了一种非典型的新型非夹心二聚体，无论 ATP 存在或不存在，该二聚体都能与 DNA 结合。 SegB 结构揭示了带状-螺旋-螺旋基序，蛋白质通过该基序与 DNA 位点特异性结合。多个相互作用的 SegB 二聚体与 DNA 的结合产生了更高阶的染色质样结构。非结构化 SegB N 末端在刺激 SegA ATP 酶活性中发挥重要的催化作用，并在 segrosome (SegA-SegB-DNA) 形成中发挥结构调节作用。电子显微镜结果还提供了与染色体组织相关的紧凑的环状segrosome结构。这些发现为古细菌染色体分离提供了新的机制视角。
Genome segregation is a vital process in all organisms. Chromosome partitioning remains obscure in Archaea, the third domain of life. Here, we investigated the SegAB system from Sulfolobus solfataricus. SegA is a ParA Walker-type ATPase and SegB is a site-specific DNA-binding protein. We determined the structures of both proteins and those of SegA-DNA and SegB-DNA complexes [1]. The SegA structure revealed an atypical, novel non-sandwich dimer that binds DNA either in the presence or absence of ATP. The SegB structure disclosed a ribbon-helix-helix motif through which the protein binds DNA site-specifically. The association of multiple interacting SegB dimers with the DNA results in a higher-order chromatin-like structure. The unstructured SegB N-terminus plays an essential catalytic role in stimulating SegA ATPase activity and an architectural regulatory role in segrosome (SegA-SegB-DNA) formation. Electron microscopy results also provide a compact ring-like segrosome structure related to chromosome organization. These findings contribute a novel mechanistic perspective on archaeal chromosome segregation.