Bacterial chemoreceptor arrays are hexagonally packed trimers of receptor dimers networked by rings of kinase and coupling proteins
Bacterial chemoreceptor arrays are hexagonally packed trimers of receptor dimers networked by rings of kinase and coupling proteins
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DOI：
10.1073/pnas.1115719109
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发表时间：
2012-03-06
影响因子：
11.1
通讯作者：
Crane, Brian R.
中科院分区：
文献类型：
--
作者：
Briegel, Ariane;Li, Xiaoxiao;Crane, Brian R.
化学感受器阵列是一种结构未知的超分子跨膜机器，它能使细菌感知周围环境并通过趋化性作出反应。我们结合了纯化的蛋白质的X射线晶体学与细胞内的天然阵列的电子冷冻断层扫描，以揭示组件跨膜受体，组氨酸激酶（CheA）和CheW偶联蛋白的排列。受体二聚体的三聚体位于六边形晶格的顶点处，以“两面对两”的构型围绕交替的CheA调节结构域（P5）和CheW偶联物的环。而CheA激酶结构域（P4）向下突出到环下方，CheA二聚化结构域（P3）连接相邻的环以形成延伸的稳定阵列。这种高度互连的蛋白质结构是细菌趋化性中跨膜信号传导的显着敏感性和合作性质的基础。
Chemoreceptor arrays are supramolecular transmembrane machines of unknown structure that allowbacteria to sense their surroundings and respond by chemotaxis. We have combined X-ray crystallography of purified proteins with electron cryotomography of native arrays inside cells to reveal the arrangement of the component transmembrane receptors, histidine kinases (CheA) and CheW coupling proteins. Trimers of receptor dimers lie at the vertices of a hexagonal lattice in a "two-facing-two" configuration surrounding a ring of alternating CheA regulatory domains (P5) and CheW couplers. Whereas the CheA kinase domains (P4) project downward below the ring, the CheA dimerization domains (P3) link neighboring rings to form an extended, stable array. This highly interconnected protein architecture underlies the remarkable sensitivity and cooperative nature of transmembrane signaling in bacterial chemotaxis.