Crystal structure of the redox-active cofactor dibromothymoquinone bound to circadian clock protein KaiA and structural basis for dibromothymoquinone's ability to prevent stimulation of KaiC phosphorylation by KaiA.
Crystal structure of the redox-active cofactor dibromothymoquinone bound to circadian clock protein KaiA and structural basis for dibromothymoquinone's ability to prevent stimulation of KaiC phosphorylation by KaiA.
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DOI：
10.1021/bi301222t
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发表时间：
2012-10-16
期刊：
影响因子：
2.9
通讯作者：
Egli M
中科院分区：
文献类型：
--
作者：
Pattanayek R;Sidiqi SK;Egli M
最近发现，在蓝藻生物钟中刺激KaiC磷酸化的KaIA蛋白被二溴胸腺酚(DBMIB)破坏了稳定性，从而揭示了KaIA作为质醌(PQ)氧化还原状态的传感器，并暗示了光通过PQ氧化还原改变对时钟进行间接控制。在这里，我们使用X射线结晶学表明，几个DBMIB结合到KaIA二聚体上。一些结合模式与N-末端KaIA假受体结构域的寡聚和/或结构域间灵活性降低相一致。DBMIB与C-末端KAIa(C-KAIa)结构域的结合以及在DBMIB存在下C-KAIa对KaiC激酶活性的刺激有限，表明辅因子可能对KAIa-KaiC结合有微弱的抑制作用。
KaiA protein that stimulates KaiC phosphorylation in the cyanobacterial circadian clock was recently shown to be destabilized by dibromothymoquinone (DBMIB), thus revealing KaiA as a sensor of the plastoquinone (PQ) redox state and suggesting an indirect control of the clock by light through PQ redox changes. Here we show using X-ray crystallography that several DBMIBs are bound to KaiA dimer. Some binding modes are consistent with oligomerization of N-terminal KaiA pseudoreceiver domains and/or reduced inter-domain flexibility. DBMIB bound to the C-terminal KaiA (C-KaiA) domain and limited stimulation of KaiC kinase activity by C-KaiA in the presence of DBMIB demonstrate that the cofactor may weakly inhibit KaiA-KaiC binding.
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DOI：
10.1126/science.1150451
发表时间：
2008-10-31
期刊：
Science (New York, N.Y.)
影响因子：
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作者：
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通讯作者：
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