Structural Insights into the FtsQ/FtsB/FtsL Complex, a Key Component of the Divisome
Structural Insights into the FtsQ/FtsB/FtsL Complex, a Key Component of the Divisome
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DOI：
10.1038/s41598-018-36001-2
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发表时间：
2018-12-24
影响因子：
4.6
通讯作者：
Lee, Hyung Ho
中科院分区：
文献类型：
--
作者：
Choi, Yuri;Kim, Jinwoo;Lee, Hyung Ho
细菌细胞分裂是一个基本过程，导致母细胞物理分离为两个子细胞，并涉及一组称为分裂体的蛋白质。其中，FtsQ/FtsB/FtsL复合物被称为支架蛋白复合物，但其整体结构和确切功能尚不清楚。在这项研究中，我们已经确定了与FtsB的C-末端片段的复合物的FtsQ的周质结构域的晶体结构，并通过体外和体内突变分析表明，FtsB的C-末端区域是FtsQ的关键结合区域。我们还获得了溶液结构的周质FtsQ/FtsB/FtsL复合物的小角X射线散射（SAXS），这揭示了它的结构组织。有趣的是，SAXS和分析凝胶过滤数据显示，FtsQ/FtsB/FtsL复合物在溶液中形成具有“Y”形状的2：2：2异六聚体组装体。基于该模型，FtsQ和FtsB/FtsL复合物的N-末端方向应该是相反的，这表明Y形FtsQ/FtsB/FtsL复合物可能很好地适合于弯曲的膜用于膜锚定。
Bacterial cell division is a fundamental process that results in the physical separation of a mother cell into two daughter cells and involves a set of proteins known as the divisome. Among them, the FtsQ/FtsB/FtsL complex was known as a scaffold protein complex, but its overall structure and exact function is not precisely known. In this study, we have determined the crystal structure of the periplasmic domain of FtsQ in complex with the C-terminal fragment of FtsB, and showed that the C-terminal region of FtsB is a key binding region of FtsQ via mutational analysis in vitro and in vivo. We also obtained the solution structure of the periplasmic FtsQ/FtsB/FtsL complex by small angle X-ray scattering (SAXS), which reveals its structural organization. Interestingly, the SAXS and analytical gel filtration data showed that the FtsQ/FtsB/FtsL complex forms a 2: 2: 2 heterohexameric assembly in solution with the "Y" shape. Based on the model, the N-terminal directions of FtsQ and the FtsB/FtsL complex should be opposite, suggesting that the Y-shaped FtsQ/FtsB/FtsL complex might fit well into the curved membrane for membrane anchoring.