CELLULAR ARCHITECTURE II: PHOTOSYNTHETIC CORE COMPLEX

细胞架构 II：光合成核心复合物

• 批准号: 7955617
• 负责人: JEN HSIN
• 金额: $ 5.75万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7955617
• 关键词: Architecture; Bacteria; Bibliography; Bioinformatics; Cells; Chromatophore; Complex; Computer Retrieval of Information on Scientific Projects Database; Electron Microscopy; Electrons; Funding; Grant; Institution; Maps; Medical; Membrane; Methods; Modeling; Molecular; Morphogenesis; Organism; Property; Proteins; Proteobacteria; Research; Research Personnel; Resolution; Resources; Rhodobacter sphaeroides; Shapes; Source; Structure; Tubular formation; Uncertainty; United States National Institutes of Health; Vesicle; base; density; dimer; flexibility; improved; molecular dynamics; simulation; two-dimensional

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The photosynthetic proteins in purple bacteria not only carry out the intricate processof energy conversion, but are also responsible for organizing the membrane intodistinct cellular compartments with well-defined shapes. Indeed, electron tomographyand electron microscopy have discovered that the photosynthetic proteins inpurple bacteria aggregate in the membrane to form independent photosyntheticunits with different shapes and sizes depending on species and protein composition.Among the membrane-bending photosynthetic proteins, the Rhodobactersphaeroides core complex is the only one thought to induce cylindrical curvature andbuild tubular vesicles in bacterial cells. However, lack of high resolution structuresfor the core complex has rendered it difficult to investigate its membrane-bendingmechanism. This project deals with a non-medical photosynthetic organism becauseof the principle importance of membrane morphogenesis for the cells of allorganisms.Previously, we constructed a rudimentary all-atom model for the Rhodobactersphaeroides core complex [1] based on the then-available two-dimensional electronmicroscope projection map [2], and showed that the core complex, a dimeric construct,bends slightly and produces curvature in the surrounding membrane. Althoughthese simulations explain the mechanism of core complex-induced membranecurvature, the curvature observed was insufficient to reproduce the known size ofthe core complex tubular vesicles due to uncertainty of the core complex structure.Recently, a three-dimensional electron miscroscope map became available,displaying a highly-bent core complex [3] and provided an opportunity to furtherfine-tune our understanding of the core complex structure. Combining the earlierall-atom model with the new three-dimensional density map [3] using the moleculardynamics flexible fitting method [4], an improved core complex model was generated[5, 6]. The large bending of the complex induced a high local curvature in themembrane, which agreed well with the size of the core complex tubular vesicles [5].Furthermore, the simulations demonstrated how the local curvature properties ofthe RC-LH1-PufX dimer propagate to form the observed long-range organizationof the Rhodobacter sphaeroides tubular vesicles [5].BIBLIOGRAPHY[1] D. Chandler, J. Hsin, C. B. Harrison, J. Gumbart, and K. Schulten. Intrinsic curvatureproperties of photosynthetic proteins in chromatophores. Biophys. J., 95:28222836,2008.[2] P. Qian, C. N. Hunter, and P. A. Bullough. The 8.5 ¿A projection structure of the coreRC-LH1-PufX dimer of Rhodobacter sphaeroides. J. Mol. Biol., 349:948960, 2005.[3] P. Qian, P. A. Bullough, and C. N. Hunter. Three-dimensional reconstructionof a membrane-bending complex: The RC-LH1-PufX core dimer of Rhodobactersphaeroides. J. Biol. Chem., 283:1400214011, 2008.[4] L. G. Trabuco, E. Villa, K. Mitra, J. Frank, and K. Schulten. Flexible fitting ofatomic structures into electron microscopy maps using molecular dynamics. Structure,16:673683, 2008. PMCID: PMC2430731.[5] J. Hsin, J. Gumbart, L. G. Trabuco, E. Villa, P. Qian, C. N. Hunter, and K. Schulten.Protein-induced membrane curvature investigated through molecular dynamicsflexible fitting. Biophys. J., 2009. In press.[6] M. K. Sener, J. Hsin, L. G. Trabuco, E. Villa, P. Qian, C. N. Hunter, and K. Schulten.Structural model and excitonic properties of the dimeric RC-LH1-PufX complex fromRhodobacter sphaeroides. Chem. Phys., 357:188197, 2009.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以出现在其他 CRISP 条目中 列出的机构是。 对于中心来说，它不一定是研究者的机构。 紫色细菌中的光合蛋白不仅执行复杂的能量转换过程，而且还负责将膜组织成具有明确形状的不同细胞区室。事实上，电子断层扫描和电子显微镜发现紫色细菌中的光合蛋白聚集。根据物种和蛋白质组成的不同，在膜中形成不同形状和大小的独立光合单位。在膜弯曲光合蛋白中，球红细菌核心复合物是只有一种想法可以在细菌细胞中诱导圆柱形弯曲并构建管状囊泡。然而，由于缺乏核心复合物的高分辨率结构，因此很难研究其膜弯曲机制，因为该项目涉及非医学光合生物。所有生物体细胞的膜形态发生。之前，我们构建了球形红细菌核心复合体的基本全原子模型 [1]基于当时可用的二维电子显微镜投影图 [2]，并表明核心复合物（一种二聚体结构）轻微弯曲并在周围膜中产生曲率，尽管这些模拟解释了核心复合物诱导膜的机制。由于核心复合体结构的不确定性，观察到的曲率不足以再现核心复合体管状囊泡的已知尺寸。最近，三维电子显微镜图变得可用，显示了高度弯曲的核心复合物[3]，并使用分子动力学灵活拟合方法[4]将早期的全原子模型与新的三维密度图[3]相结合，为进一步微调我们对核心复合物结构的理解提供了机会。 ]，生成了改进的核心复合体模型[5, 6]，复合体的大弯曲引起膜的高局部曲率，这与核心复合体管状囊泡的尺寸非常吻合。 [5].此外，模拟演示了 RC-LH1-PufX 二聚体的局部曲率特性如何传播以形成观察到的球形红细菌管状囊泡的远程组织 [5]。参考书目 [1] D. Chandler, J. Hsin、C. B. Harrison、J. Gumbart 和 K. Schulten。 Biophys 中光合蛋白的曲率特性，95：2822 2836，2008。[2] P.Qian，C.N.Hunter 和 P.A.Bullough。球形红细菌的 coreRC-LH1-PufX 二聚体的投影结构，J. Mol.，349:948 960, 2005。[3] P. Qian、P. A. Bullough 和 C. N. Hunter。 . -弯曲复合物：Rhodobactersphaeroides J 的 RC-LH1-PufX 核心二聚体。 Biol. Chem., 283:14002 14011, 2008.[4] L. G. Trabuco、E. Villa、K. Mitra、J. Frank 和 K. Schulten。使用分子动力学将原子结构灵活拟合到电子显微镜图中。 16:673 683, 2008.PMCID: PMC2430731.[5] Hsin、J. Gumbart、L. G. Trabuco、E. Villa、P. Qian、C. N. Hunter 和 K. Schulten。通过分子动力学柔性拟合研究蛋白质诱导的膜曲率，2009 年。正在出版。 M.K.Sener、J.Hsin、L.G.Trabuco、E.Villa、P.Qian、C.N.Hunter 和 K. Schulten.来自球形红细菌的二聚体 RC-LH1-PufX 复合物的结构模型和激子特性，357:188 197, 2009。