Molecular structure and regulation of phototropin kinase by blue light.
Molecular structure and regulation of phototropin kinase by blue light.
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DOI：
10.1016/j.bbapap.2007.09.010
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发表时间：
2008
期刊：
影响因子：
--
通讯作者：
S. Tokutomi;D. Matsuoka;K. Zikihara
中科院分区：
文献类型：
--
作者：
S. Tokutomi;D. Matsuoka;K. Zikihara
趋光素（Phototropin, phot）是植物中的一种蓝光感受器，介导向光性、叶绿体运动、气孔打开和叶片扩张。光分子有两个感光结构域，LOV 1和LOV 2，位于n端一半，c端一半形成丝氨酸/苏氨酸激酶。光起着蓝光调节蛋白激酶的作用。每个LOV结构域结合一个FMN，在蓝光吸收时发生独特的循环反应，诱导蛋白质片段的构象变化，导致激酶活性的调节，其中LOV2在开关中起主导作用，LOV1的作用是减弱光敏感性。光激酶被归类为AGC激酶，因为除了缺乏疏水基序和激活环中存在额外的氨基酸序列外，共识氨基酸残基和基序都很保守。二级结构预测和三维结构模拟表明，光激酶的α/β折叠与PKA的催化亚基相似。额外的序列形成额外的螺旋和环。LOV2结构域与光激酶的对接模拟为了解光激酶光调控的分子机制提供了有用的信息。
Phototropin (phot) is a blue light photoreceptor in plants that mediates phototropism, chloroplast movement, stomata opening and leaf expansion. The phot molecule has two photoreceptive domains, LOV 1 and 2, in the N-terminal half and the C-terminal half forms Ser/Thr kinase. Phot acts as a blue light-regulated protein kinase. Each LOV domain binds a FMN and undergoes a unique cyclic reaction upon blue light absorption that induces conformational changes in the protein moiety and leads to regulation of the kinase activity, in which LOV2 plays a predominant role in the switching and LOV1 acts to attenuate the light sensitivity. Phot kinase is classified into the AGC kinase group since the consensus amino acid residues and the motifs are well conserved except for the lack of the hydrophobic motif and the presence of additional amino acid sequence in the activation loop. Secondary structure prediction and 3D structure simulation show a α/β fold of the phot kinase similar to that of the catalytic subunit of PKA. The additional sequence forms an extra helix and loops. Docking simulation of the LOV2 domain with phot kinase provided useful information regarding the molecular mechanism underlying the photoregulation of phot kinase.