N- and C-terminal flanking regions modulate light-induced signal transduction in the LOV2 domain of the blue light sensor phototropin 1 from Avena sativa
N- and C-terminal flanking regions modulate light-induced signal transduction in the LOV2 domain of the blue light sensor phototropin 1 from Avena sativa
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DOI：
10.1021/bi701543e
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发表时间：
2007-12-11
期刊：
影响因子：
2.9
通讯作者：
Moffat, Keith
中科院分区：
文献类型：
--
作者：
Halavaty, Andrei S.;Moffat, Keith
光感受器的光感控制植物的向光性、叶绿体运动、气孔开放和叶片扩展。了解这些过程的调节分子机制需要光感受器动力学的定量描述。我们专注于一个光驱动的信号转导机制在LOV 2域（LOV，光，氧，电压）的蓝光感光器phototropin I从燕麦（燕麦）。在105和293 K下测定了燕麦LOV 2构建体（包括残基Leu 404-Leu 546（LOV 2（404-546）暗态和亮态的高分辨率晶体结构。在所有四种结构中，LOV 2（404-546）表现出典型的Per-ARNT-Sim（PAS）折叠，其侧翼是额外的保守的N-末端转角-螺旋-转角基序和含有两亲性J α螺旋的C-末端侧翼区。这些区域停靠在LOV 2核心结构域上，并掩埋核心结构域的中心β-折叠的几个疏水残基，否则这些疏水残基将暴露于溶剂。LOV 2（404-546）的轻结构揭示了Cys 450和黄素单肽（FMN）的C4 a原子之间的共价键的形成导致FMN结合口袋中的氢键网络的局部重排。这些重排与蛋白质表面上Asn 414-Asp 515氢键的破坏以及LOV 2（404-546）的N-和C-末端侧翼区的置换相关，这两者都构成结构信号。
Light sensing by photoreceptors controls phototropism, chloroplast movement, stomatal opening, and leaf expansion in plants. Understanding the molecular mechanism by which these processes are regulated requires a quantitative description of photoreceptor dynamics. We focus on a light-driven signal transduction mechanism in the LOV2 domain (LOV, light, oxygen, voltage) of the blue light photoreceptor phototropin I from A vena sativa (oat). High-resolution crystal structures of the dark and light states of an oat LOV2 construct including residues Leu404 through Leu546 (LOV2 (404-546)) have been determined at 105 and 293 K. In all four structures, LOV2 (404-546) exhibits the typical Per-ARNT-Sim (PAS) fold, flanked by an additional conserved N-terminal turn-helix-turn motif and a C-terminal flanking region containing an amphipathic J alpha helix. These regions dock on the LOV2 core domain and bury several hydrophobic residues of the central beta-sheet of the core domain that would otherwise be exposed to solvent. Light structures of LOV2 (404-546) reveal that formation of the covalent bond between Cys450 and the C4a atom of the flavin mononucleotide (FMN) results in local rearrangement of the hydrogen-bonding network in the FMN binding pocket. These rearrangements are associated with disruption of the Asn414-Asp515 hydrogen bond on the surface of the protein and displacement of the N- and C-terminal flanking regions of LOV2 (404-546), both of which constitute a structural signal.