The ATP-mediated regulation of KaiB-KaiC interaction in the cyanobacterial circadian clock.
The ATP-mediated regulation of KaiB-KaiC interaction in the cyanobacterial circadian clock.
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DOI：
10.1371/journal.pone.0080200
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Ishiura M
中科院分区：
文献类型：
--
作者：
Mutoh R;Nishimura A;Yasui S;Onai K;Ishiura M
蓝藻生物钟振荡器由三种生物钟蛋白KaiA、KaiB和KaiC组成，三种生物钟蛋白之间的相互作用在体外产生生物钟振荡。然而，这些相互作用的调节仍有待解决。在这里，我们证明了ATP调节KaiB-KaiC复合物的形成。在没有ATP的情况下，KaiC是单体（KaiC1mer），并与KaiB形成复合物。在KaiB-KaiC1mer复合物中加入ATP和Mg~（2+）（Mg-ATP）而不是仅加入ATP，可诱导KaiC的六聚化和KaiB从KaiB-KaiC1mer复合物中的释放，表明Mg-ATP和KaiB相互竞争KaiC。在ATP和Mg2+（Mg-ATP）存在下，KaiC与Mg-ATP结合形成六聚体ATP酶（KaiC6mer），并与KaiB形成复合物，而KaiC与ATP和Mg-ATP类似物等不可水解底物结合形成六聚体ATP酶（KaiC6mer）。KaiC的N-末端结构域蛋白与KaiB形成复合物，而不是其C-末端结构域蛋白，表明KaiC通过其N-末端结构域与KaiB结合。缺乏N-末端ATP酶活性的突变体KaiC6mer不与KaiB形成复合物，而缺乏C-末端ATP酶活性的突变体则与KaiB形成复合物。因此，KaiC的N-末端结构域负责KaiB-KaiC复合物的形成，并且KaiB-KaiC6mer复合物的形成需要结合到KaiC6mer上的N-末端ATP酶基序的ATP的水解。KaiC 6聚体与ADP和氟化铝（被认为模拟ADP-Pi状态）六聚化后与KaiB形成复合物，表明KaiB能够与结合有ADP-Pi的KaiC 6聚体缔合。
The cyanobacterial circadian clock oscillator is composed of three clock proteins—KaiA, KaiB, and KaiC, and interactions among the three Kai proteins generate clock oscillation in vitro. However, the regulation of these interactions remains to be solved. Here, we demonstrated that ATP regulates formation of the KaiB-KaiC complex. In the absence of ATP, KaiC was monomeric (KaiC1mer) and formed a complex with KaiB. The addition of ATP plus Mg2+ (Mg-ATP), but not that of ATP only, to the KaiB-KaiC1mer complex induced the hexamerization of KaiC and the concomitant release of KaiB from the KaiB-KaiC1mer complex, indicating that Mg-ATP and KaiB compete each other for KaiC. In the presence of ATP and Mg2+ (Mg-ATP), KaiC became a homohexameric ATPase (KaiC6mer) with bound Mg-ATP and formed a complex with KaiB, but KaiC hexamerized by unhydrolyzable substrates such as ATP and Mg-ATP analogs, did not. A KaiC N-terminal domain protein, but not its C-terminal one, formed a complex with KaiB, indicating that KaiC associates with KaiB via its N-terminal domain. A mutant KaiC6mer lacking N-terminal ATPase activity did not form a complex with KaiB whereas a mutant lacking C-terminal ATPase activity did. Thus, the N-terminal domain of KaiC is responsible for formation of the KaiB-KaiC complex, and the hydrolysis of the ATP bound to N-terminal ATPase motifs on KaiC6mer is required for formation of the KaiB-KaiC6mer complex. KaiC6mer that had been hexamerized with ADP plus aluminum fluoride, which are considered to mimic ADP-Pi state, formed a complex with KaiB, suggesting that KaiB is able to associate with KaiC6mer with bound ADP-Pi.
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影响因子：
4.8
作者：
Hayashi, F;Itoh, N;Ishiura, M
通讯作者：
Ishiura, M
DOI：
10.1073/pnas.85.23.8958
发表时间：
1988-12-01
影响因子：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1073/pnas.0403906101
发表时间：
2004-09-21
影响因子：
11.1
作者：
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