Structural basis for light-dependent signaling in the dimeric LOV domain of the photosensor YtvA
Structural basis for light-dependent signaling in the dimeric LOV domain of the photosensor YtvA
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DOI：
10.1016/j.jmb.2007.07.039
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发表时间：
2007-10-12
影响因子：
5.6
通讯作者：
Moffat, Keith
中科院分区：
文献类型：
--
作者：
Moeglich, Andreas;Moffat, Keith
该光传感器与黄素单核苷酸结合，调节枯草芽孢杆菌对蓝光的应激反应。它属于光-氧-电压(LOV)蛋白家族，最先在植物促光体中被描述，并形成Per-Arnt-Sim(PAS)超家族的一个亚群。在这里，我们报告了YTVA的LOV结构域在其暗和亮状态下的三维结构。该蛋白采用所有PAS结构域共同的全球折叠，并通过疏水界面进行二聚。将C末端直接连接到LOV结构域的核心，一个α螺旋延伸到溶剂中。光吸收导致保守的半胱氨酸残基和FMN环的C(4a)原子之间形成共价键，这引发了整个LOV结构域的重排。同时，在暗结构和亮结构中，二聚体蛋白质的两个亚基相对于彼此旋转5度。这种小的四级结构变化可能是YTVA活性受光调控机制的一个组成部分。在结构和信号机制方面，YtwA不同于植物趋光素，而更接近于原核生物的血红素结合PAS结构域。(C)2007爱思唯尔有限公司。保留所有权利。
The photosensor YtvA binds flavin mononucleotide and regulates the general stress reaction in Bacillus subtilis in response to blue light illumination. It belongs to the family of light-oxygen-voltage (LOV) proteins that were first described in plant phototropins and form a subgroup of the Per-Arnt-Sim (PAS) superfamily. Here, we report the three-dimensional structure of the LOV domain of YtvA in its dark and light states. The protein assumes the global fold common to all PAS domains and dimerizes via a hydrophobic interface. Directly C-terminal to the core of the LOV domain, an alpha-helix extends into the solvent. Light absorption causes formation of a covalent bond between a conserved cysteine residue and atom C(4a) of the FMN ring, which triggers rearrangements throughout the LOV domain. Concomitantly, in the dark and light structures, the two subunits of the dimeric protein rotate relative to each other by 5 degrees. This small quaternary structural change is presumably a component of the mechanism by which the activity of YtvA is regulated in response to light. In terms of both structure and signaling mechanism, YtvA differs from plant phototropins and more closely resembles prokaryotic heme-binding PAS domains. (C) 2007 Elsevier Ltd. All rights reserved.