Coiled-coil dimerization of the LOV2 domain of the blue-light photoreceptor phototropin 1 from Arabidopsis thaliana
Coiled-coil dimerization of the LOV2 domain of the blue-light photoreceptor phototropin 1 from Arabidopsis thaliana
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DOI：
10.1107/s1744309113029199
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发表时间：
2013-12-01
影响因子：
0.9
通讯作者：
Moffat, Keith
中科院分区：
文献类型：
--
作者：
Halavaty, Andrei S.;Moffat, Keith
在由Per-Arnt-Sim（PAS）结构域介导的信号转导和二聚化中的关键作用由位于这些结构域的结构相似的α/β核心侧翼的α-螺旋接头发挥。然而，晶体堆积力和PAS结构域的不同构建体长度和序列影响接头相对于核心的最终长度和取向，并在接头功能的确切机制中产生不确定性。因此，分离的PAS结构域构建体和/或全长含PAS蛋白内的接头的结构表征和比较对于阐明机制是重要的。植物蓝光光感受器光致蛋白具有两个N-末端基于黄素单核苷酸的光、氧或电压（LOV）结构域（LOV 1和LOV 2），其包括PAS家族的亚类和一个C-末端丝氨酸/苏氨酸激酶结构域，其酶活性受蓝光调节。拟南芥向光蛋白1和向光蛋白2 LOV 1-结构域构建体的暗适应状态晶体结构是已知的，其侧翼为N-末端A 'α螺旋和向光蛋白2核心LOV 2结构域的结构。在这里，A.拟南芥趋光蛋白1 LOV 2结构域已被确定在其暗适应状态。核心的两侧是N-末端A 'α螺旋和C-末端J α螺旋，与先前报道的燕麦向光蛋白1 LOV 2的结构相似。与单体A. sativa LOV 2、苜蓿A. thaliana LOV 2是二聚体，其中两个A ′ α螺旋在二聚体界面处采用剪刀样取向并形成短α-螺旋卷曲螺旋。J α螺旋主要与β折叠相互作用，并在卷曲螺旋形成和二聚化中发挥作用。
A key role in signal transduction and dimerization mediated by Per-Arnt-Sim (PAS) domains is played by alpha-helical linkers that flank the structurally similar alpha/beta cores of these domains. However, crystal-packing forces and the different construct lengths and sequences of the PAS domains influence the final length and orientation of the linkers relative to the core and create uncertainty in the exact mechanism of the linker function. Thus, structural characterization and comparison of the linkers within isolated PAS-domain constructs and/or full-length PAS-containing proteins is important for clarification of the mechanism. The plant blue-light photoreceptors phototropins possess two N-terminal flavin mononucleotide-based light, oxygen or voltage (LOV) domains (LOV1 and LOV2) that comprise a subclass of the PAS family and one C-terminal serine/threonine kinase domain whose enzymatic activity is regulated by blue light. The dark-adapted state crystal structures of the Arabidopsis thaliana phototropin 1 and phototropin 2 LOV1-domain constructs flanked by an N-terminal A 'alpha helix and the structure of the phototropin 2 core LOV2 domain are known. Here, the crystal structure of the A. thaliana phototropin 1 LOV2 domain has been determined in its dark-adapted state. The core is flanked by an N-terminal A 'alpha helix and a C-terminal J alpha helix similar to those in the previously reported structure of Avena sativa phototropin 1 LOV2. In contrast to the monomeric A. sativa LOV2, A. thaliana LOV2 is a dimer in which two A 'alpha helices adopt a scissor-like orientation at the dimer interface and form a short alpha-helical coiled coil. The J alpha helix predominantly interacts with the beta-sheet and plays a role in coiled-coil formation and dimerization.