Allosteric communication between DNA-binding and light-responsive domains of diatom class I aureochromes.
Allosteric communication between DNA-binding and light-responsive domains of diatom class I aureochromes.
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硅藻I类AureOchromes的DNA结合和光反应域之间的变构通信。
DOI：
10.1093/nar/gkw420
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发表时间：
2016-07-08
影响因子：
14.9
通讯作者：
Kottke T
中科院分区：
文献类型：
--
作者：
Banerjee A;Herman E;Serif M;Maestre-Reyna M;Hepp S;Pokorny R;Kroth PG;Essen LO;Kottke T
在包括硅藻在内的几种藻类中发现的金色素蓝光受体的模块化结构是独特的，其LOV型光感受器结构域融合到其推定效应器的C-末端，N-末端DNA结合bZIP模块。金色素的光依赖性信号传导机制的结构和功能的理解是有限的，尽管它们作为光遗传学工具的承诺。我们表明，I类aureochromes 1a和1c的硅藻Phaeodactylum三角褐指藻的光独立的昼夜节律进行调节。这些aureochromes能够形成功能性的同源和异源二聚体，其以不依赖于光的方式识别典型的“aureo box”TGACGT内的ACGT核心序列。bZIP结构域在双链体DNA结合状态下具有更折叠和更不灵活但延伸的构象。FT-IR光谱的存在和不存在的DNA显示光依赖性的螺旋展开的LOV域，这导致在bZIP区域的构象变化。结合金色素的DNA的溶液结构指向一个倾斜的方向，进一步验证了分子动力学模拟。我们建议，aureochrome信号依赖于从LOV bZIP的变构途径，结果在附近的bZIP-DNA界面的构象变化，而没有对结合亲和力的重大影响。
The modular architecture of aureochrome blue light receptors, found in several algal groups including diatoms, is unique by having the LOV-type photoreceptor domain fused to the C-terminus of its putative effector, an N-terminal DNA-binding bZIP module. The structural and functional understanding of aureochromes’ light-dependent signaling mechanism is limited, despite their promise as an optogenetic tool. We show that class I aureochromes 1a and 1c from the diatom Phaeodactylum tricornutum are regulated in a light-independent circadian rhythm. These aureochromes are capable to form functional homo- and heterodimers, which recognize the ACGT core sequence within the canonical ‘aureo box’, TGACGT, in a light-independent manner. The bZIP domain holds a more folded and less flexible but extended conformation in the duplex DNA-bound state. FT-IR spectroscopy in the absence and the presence of DNA shows light-dependent helix unfolding in the LOV domain, which leads to conformational changes in the bZIP region. The solution structure of DNA bound to aureochrome points to a tilted orientation that was further validated by molecular dynamics simulations. We propose that aureochrome signaling relies on an allosteric pathway from LOV to bZIP that results in conformational changes near the bZIP-DNA interface without major effects on the binding affinity.