Structural basis of the day-night transition in a bacterial circadian clock.
Structural basis of the day-night transition in a bacterial circadian clock.
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DOI：
10.1126/science.aag2516
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发表时间：
2017-03-17
期刊：
影响因子：
--
通讯作者：
Partch CL
中科院分区：
文献类型：
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作者：
Tseng R;Goularte NF;Chavan A;Luu J;Cohen SE;Chang YG;Heisler J;Li S;Michael AK;Tripathi S;Golden SS;LiWang A;Partch CL
生物钟是无处不在的计时系统，它与昼夜同步地诱导生物活动的节奏。在蓝藻中，时间是由翻译后时钟产生的，该时钟由KaIA、Kaib和KaiC蛋白以及一组输出信号蛋白Sasa和Cika组成，这些输出信号蛋白转导这种节奏来控制基因的表达。在这里，我们描述了Kaib-Kaic、KaIA-Kaib-KaiC和Cika-Kaib络合物的晶体和核磁共振结构。它们揭示了Kaib的变性特性和KaiC的三磷酸腺苷后水解态是如何创建一个中枢的，夜间信号事件围绕这个中枢旋转，包括KaIA的失活和相互拮抗的信号蛋白Sasa和Cika的相互调节。
Circadian clocks are ubiquitous timing systems that induce rhythms of biological activities in synchrony with night and day. In cyanobacteria, timing is generated by a posttranslational clock consisting of KaiA, KaiB, and KaiC proteins and a set of output signaling proteins, SasA and CikA, which transduce this rhythm to control gene expression. Here, we describe crystal and nuclear magnetic resonance structures of KaiB-KaiC, KaiA-KaiB-KaiC, and CikA-KaiB complexes. They reveal how the metamorphic properties of KaiB, a protein that adopts two distinct folds, and the post–adenosine triphosphate hydrolysis state of KaiC create a hub around which nighttime signaling events revolve, including inactivation of KaiA and reciprocal regulation of the mutually antagonistic signaling proteins, SasA and CikA.