Blue light-induced LOV domain dimerization enhances the affinity of Aureochrome 1a for its target DNA sequence.
Blue light-induced LOV domain dimerization enhances the affinity of Aureochrome 1a for its target DNA sequence.
复制标题
DOI：
10.7554/elife.11860
复制
发表时间：
2016-01-12
期刊：
影响因子：
7.7
通讯作者：
Schlichting I
中科院分区：
文献类型：
--
作者：
Heintz U;Schlichting I
合成光遗传学工具的设计在过去几年中得到了迅速发展，这些工具可以对以前无法进行光遗传学控制的生物过程进行精确的时空控制。此类工具的合理设计需要对天然光感受器中的变构光信号传导有详细的了解。为了了解传感器和效应器域之间的变构通信，需要表征所有相关的信号传导状态。在这里，我们描述了来自三角褐指藻 (PtAu1a) 的光氧电压 (LOV) 转录因子 Aureochrome 1a 的光依赖性 DNA 结合机制，并展示了暗态 LOV 单体和完全光适应的 LOV 二聚体的晶体结构。结合氢/氘交换、溶液散射数据和 DNA 结合实验，我们的研究揭示了 LOV 和碱性区域亮氨酸拉链 DNA 结合结构域之间的光敏相互作用，与 LOV 二聚化一起导致 PtAu1a 的 DNA 亲和力的调节。我们讨论了这些结果对于设计基于 LOV 的合成光传感器及其在光遗传学中的应用的影响。 DOI：http://dx.doi.org/10.7554/eLife.11860.001 对阳光做出反应的能力对于多种生命形式的生存非常重要。许多生物体，包括人类、植物、细菌和藻类，都使用称为光感受器的特殊蛋白质来感知光。这些蛋白质能够将光传输的信息转化为各种生物活动。感光器的结构可以分为不同的部分，每个部分都有专门的作用。例如，光感受器的感光区域通常与能够吸收光的称为发色团的小分子结合。这种光吸收会导致光感受器发生变化，最终传递到可以与 DNA 结合或执行某些其他类型的生物活性的蛋白质的一部分。这种活动会触发进一步的过程，从而形成有机体对入射光的反应。金色素是检测蓝光的光感受器，存在于藻类中。金色素的光感应和 DNA 结合部分的排列方式与大多数相关光感受器中的排列方式不同。这就提出了关于光信号如何传输到蛋白质的 DNA 结合部分以及这如何影响金色素的 DNA 结合的问题。通过结合生物物理和结构方法，Heintz 和 Schlichting 现在提供了有关蓝光导致三角褐指藻中金色素 1a 光感受器结构变化的详细信息。这表明，当暴露在光线下时，光感受器的感光部分（称为 LOV 结构域）会与 DNA 结合部分分离，并与第二个分子的 LOV 区域结合。这有助于蛋白质与 DNA 结合。最近，合成光感受器被设计成使用金色素的光传感部分。因此，海因茨和施利希廷的研究结果不仅有助于对光感受器中光信号的基本理解，还可用于帮助开发用于研究、医学或工业的光控人造蛋白质。 DOI：http://dx.doi.org/10.7554/eLife.11860.002
The design of synthetic optogenetic tools that allow precise spatiotemporal control of biological processes previously inaccessible to optogenetic control has developed rapidly over the last years. Rational design of such tools requires detailed knowledge of allosteric light signaling in natural photoreceptors. To understand allosteric communication between sensor and effector domains, characterization of all relevant signaling states is required. Here, we describe the mechanism of light-dependent DNA binding of the light-oxygen-voltage (LOV) transcription factor Aureochrome 1a from Phaeodactylum tricornutum (PtAu1a) and present crystal structures of a dark state LOV monomer and a fully light-adapted LOV dimer. In combination with hydrogen/deuterium-exchange, solution scattering data and DNA-binding experiments, our studies reveal a light-sensitive interaction between the LOV and basic region leucine zipper DNA-binding domain that together with LOV dimerization results in modulation of the DNA affinity of PtAu1a. We discuss the implications of these results for the design of synthetic LOV-based photosensors with application in optogenetics. DOI: http://dx.doi.org/10.7554/eLife.11860.001 The ability to react to sunlight is important for the survival of a wide range of lifeforms. Many organisms, including humans, plants, bacteria and algae, sense light using specialized proteins called photoreceptors. These proteins are able to translate the information transported by light into various biological activities. The structure of a photoreceptor can be broken down into different parts, each with a specialized role. For example, the light-sensing region of a photoreceptor typically binds to small molecules called chromophores that are able to absorb light. This light absorption causes changes in the photoreceptor that are ultimately transmitted to a part of the protein that can bind to DNA or perform some other type of biological activity. This activity triggers further processes that build up to the organism’s reaction to the incoming light. Aureochromes are photoreceptors that detect blue light and are found in algae. The light-sensing and DNA-binding parts of aureochromes are arranged in a different way to the arrangement seen in most related photoreceptors. This raises questions about how the light signal is transmitted to the DNA-binding part of the protein and how this affects the DNA binding of aureochromes. By using a combination of biophysical and structural methods, Heintz and Schlichting now provide detailed information about the structural changes that blue light causes in the Aureochrome 1a photoreceptor found in the algae Phaeodactylum tricornutum. This shows that when exposed to light, the light-sensing part of the photoreceptor, called LOV domain, detaches from the DNA binding part and binds to the LOV region of a second molecule. This helps the protein to bind to DNA. Recently, synthetic photoreceptors have been engineered that use the light-sensing part of aureochromes. Therefore, as well as contributing to the fundamental understanding of light signaling in photoreceptors, Heintz and Schlichting’s findings can be used to help develop light-controllable artificial proteins for use in research, medicine or industry. DOI: http://dx.doi.org/10.7554/eLife.11860.002