Phytochromes: Structural Perspectives on Photoactivation and Signaling

光敏色素：光活化和信号传导的结构视角

• 批准号: 10708835
• 负责人: RICHARD DAVID VIERSTRA
• 金额: $ 32.34万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10708835
• 关键词: Acceleration; Advanced Development; Agriculture; Architecture; Back; Behavior; Bilin; Binding; Biochemical; Biology; Biotechnology; Collection; Coupled; Cryoelectron Microscopy; Crystallography; Data; Deuterium; Ecosystem; Electrons; Engineering; Environment; Event; Evolution; Family; Genetic Transcription; Goals; Growth and Development function; Head; Health; Human; Hydrogen; Influentials; Isomerism; Kinetics; Knowledge; Length; Life; Light; Link; Maps; Mass Spectrum Analysis; Measures; Medical; Membrane Proteins; Microscopic; Mission; Modality; Modeling; Molecular Conformation; Nature; Organism; Output; Paint; Pathway interactions; Perception; Performance; Photochemistry; Photons; Photoperiod; Photoreceptors; Physiological Processes; Phytochrome; Plant Model; Plants; Positioning Attribute; Process; Protein Isoforms; Proteins; Reaction; Reagent; Research; Signal Transduction; Source; Structure; Surface; Synchrotrons; Tail; Temperature; Temperature Sense; Tetrapyrroles; Time; Time Perception; Tissue imaging; Transcription Repressor; United States National Institutes of Health; Variant; Work; X-Ray Crystallography; absorption; chromophore; comparative; conformer; dimer; driving force; fluorophore; human pathogen; improved; information gathering; light intensity; member; microbial; microorganism; novel; optogenetics; oxidation; particle; pathogen; photoactivation; plant growth/development; protein-histidine kinase; three dimensional structure; three-dimensional modeling; tool; transcription factor; x-ray free-electron laser

PROJECT SUMMARY Almost all cellular organisms employ an array of photoreceptors to detect their light environment. Arguably the most influential are the phytochromes (Phys), a diverse group essential for plant development and the behavior of many bacterial, fungal, and algal species. By reversible photointerconversion of their bilin (or open-chain tetrapyrrole) chromophores between red light-absorbing Pr and far-red light-absorbing Pfr states, Phys act as photoswitches in various signaling cascades responsive to light intensity, duration, direction, and spectral quality. Moreover, through the thermal reversion of Pfr back to Pr, some Phys sense temperature through enthalpic effects on this reaction, and perceive photoperiod through the nighttime depletion of Pfr. The cumulative effects of this Pr/Pfr interconversion impact numerous physiological processes important to agriculture and the biology of harmful plant and human pathogens. In addition, their unique photochemistries provide invaluable optogenetic tools, including novel fluorophores for tissue imaging, and engineered photoswitches for regulating cellular events with remarkable temporal and spatial precision. Recently, we made great strides in understanding how Phys signal, with emerging structures suggesting that microbial and plant Phys use two distinct output modalities. Both start with light-triggered isomerization of the bilin, which drives a - stranded to -helical rearrangement of a hairpin loop that links the signature PHY and GAF domains. While photoactivated microbial Phys then connect torsional strain generated within the dimer to regulate an appended output domain (typically with histidine kinase activity), plant Phys have rearranged their domain organization to create a photosensitive dimeric platform that likely enables reversible binding and eventual degradation of the family of PIF transcriptional repressors. While current models helped illuminate gross changes required for endstate conversion, the intermediates of photoexcitation and ensuing structural changes necessary for creating a signaling-competent Pfr state remain uncertain. The objectives of this proposal are to complete these pictures through continued X-ray crystallographic and cryo-electron microscopic approaches followed by informed biochemical analyses of representatives in their inactive and active states. Specific aims are to: (1) exploit time-resolved serial X-ray crystallography to structurally define the intermediates generated by Phys after photon absorption; (2) generate more comprehensive structures of bacterial Phys, including models of full- length dimeric photoreceptors with their signal output modules; (3) develop a model for how plant Phys signal through structural studies on Pfr; (4) apply steady-state and time-resolved protein surface mapping to support the Phy photoconversion pathway(s) seen structurally; (5) develop models of Phys interacting with their downstream effectors, and (6) appreciate how diversity among plant Phy enables thermal/time perception by specific isoforms. Taken together, this project will provide an essential framework to better appreciate the structure, allosteric mechanisms, and evolution of the Phy superfamily. Understanding how microorganisms and plants sense light, temperature, and time would then have important ramifications for improving the agricultural performance of crop plants, understanding microbial ecosystems, controlling medically-relevant pathogens, and furthering the application of Phys as optogenetic reagents.

项目摘要 几乎所有的细胞生物都会雇用一系列光感受器来检测其光环境。可以说最多 有影响力的是植物色素（物理），这是一个对植物发育和许多细菌行为至关重要的潜水员群体， 真菌和藻类物种。通过可逆的光插入其bilin（或开链四吡咯）发色团 在红色的吸收光PR和远红色的光线pfr状态之间，物理充当各种信号传导中的照片开关 级联反应光强度，持续时间，方向和光谱质量。此外，通过 PFR回到PR，通过对该反应的焓影响进行某些物理感知温度，并通过 PFR的夜间耗尽。该PR/PFR互连的累积效应影响了许多生理 对农业和有害植物和人类病原体的生物学重要的过程。此外，他们的独特 光化学提供了宝贵的光遗传学工具，包括用于组织成像的新型荧光团和设计的 用于控制具有显着临时和空间精度的细胞事件的照片开关。 最近，我们在理解物理信号方面取得了长足的进步，新兴结构表明微生物和 植物物理使用两种不同的输出方式。两者都是从bilin的光触发异构化开始的，该异构化驱动A- 滞留在连接签名PHY和GAF域的发夹环的螺旋重排。同时光活化 然后，微生物物理连接在二聚体内生成的扭转应变以调节附加的输出域（通常 随着组氨酸激酶的活性），植物物理重新排列了其域组织以创建光敏二聚体 可能使PIF转录表示家庭的可逆绑定和最终降解的平台。 虽然当前的模型有助于阐明端州转换所需的总体变化，但光激发的中间体 并确保创建具有信号能力的PFR状态所需的结构性变化尚不确定。 该提案的目标是通过持续的X射线晶体学和冷冻电子完成这些图片 显微镜方法，然后进行了明智的生化分析，以表现出其活性和活性状态。 具体目的是：（1）利用时间分辨的串行X射线晶体学以在结构上定义生成的中间体 通过滥用光子后的物理； （2）生成更全面的细菌性结构，包括 长度二聚体光感受器，其信号输出模块； （3）开发一个模型，以通过植物物理信号通过 PFR的结构研究； （4）应用稳态和时间分辨蛋白表面映射以支持PHY 在结构上看到的光转化途径； （5）开发物理模型与其下游效应相互作用，以及 （6）欣赏植物PHY之间的多样性如何通过特定的同工型实现热/时间感知。 综上所述，该项目将提供一个必要的框架，以更好地欣赏结构，变构机制， 和PHY超家族的演变。了解微生物和植物如何感知光，温度和时间 然后，将对改善作物植物的农业表现产生重要的影响，了解微生物 生态系统，控制与医学相关的病原体，并促进物理作为光遗传试剂的应用。

项目成果

The structure of Arabidopsis phytochrome A reveals topological and functional diversification among the plant photoreceptor isoforms.

• DOI: 10.1038/s41477-023-01435-8
• 发表时间: 2023-07
• 期刊: NATURE PLANTS
• 影响因子: 18
• 作者: Burgie, E. Sethe;Li, Hua;Gannam, Zachary T. K.;McLoughlin, Katrice E.;Vierstra, Richard D.;Li, Huilin
• 通讯作者: Li, Huilin

Plant phytochrome B is an asymmetric dimer with unique signalling potential.

• DOI: 10.1038/s41586-022-04529-z
• 发表时间: 2022-04
• 期刊: Nature
• 影响因子: 64.8