Shapes of Biomacromolecular Complexes by Solid-State NuclearMagnetic Resonance

固态核磁共振研究生物大分子复合物的形状

• 批准号: 9604860
• 负责人: Jacob Schaefer
• 金额: $ 48万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-01 至 2001-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9604860&HistoricalAwards=false
• 关键词: Shapes; Biomacromolecular; Complexes; Solid; State

9604860 Schaefer The goal of the work is the characterization by solid-state NMR of proteins and DNA that are part of a supramolecular structure or assembly. These include cross-linked proteins in insect cuticle, marine organisms and plant cell walls, as well as proteins encapsulated in stabilizing lyoprotectant matrices, and DNA compacted by dendrimer-like macromolecules. Dipolar couplings between stable-isotope labels will be measured directly in these complicated biomacromolecular assemblies by REDOR (Rotational-echo double resonance) and REDOR-like NMR recoupling experiments. In the work on insect, mussel, and plant proteins, specific chemical questions will be answered as to how these structures are cross-linked and stabilized. A search will be made for new ways to stabilize fragile protein complexes in a buffered sugar glass. These matrices will then be used to examine the natural-substrate reaction intermediates of enolpyruvylshikimate 3-phosphate synthase which have been trapped in the glass. Finally, a dopant will be created for dynamic nuclear polariation experiments by burying a stable free radical in the core of an amphiphilic particle that complexes proteins and compacts DNA. REDOR will be used to characterize the local structure and the resulting distances will be used as constraints in molecular dynamics simulations designed to visualize the overall shapes of the complexes. Many biochemical and biophysical processes are carried out by or in molecular superstructures. These superstructures are macromolecular complexes or aggregates for which there is no atomic-level structural information because they are not soluble (no solution NMR) and don't crystalize (no x-ray crystallography). This work will provide specific insights into important practical problems (insect pest management, barnacle fouling of ship hulls, enzyme reaction pathways, DNA compaction) and generate a new kind of biophysical structural tool with atomic-level resolution (solid-state NMR) that is applic able to otherwise intractable systems.

[9604860]谢弗这项工作的目标是通过固态核磁共振表征蛋白质和DNA，这些蛋白质和DNA是超分子结构或组装的一部分。这些包括昆虫角质层、海洋生物和植物细胞壁中的交联蛋白，以及包裹在稳定的lyoprotectant基质中的蛋白质，以及由树突状大分子压实的DNA。在这些复杂的生物大分子组合中，稳定同位素标记之间的偶极耦合将通过REDOR（旋转回声双共振）和类似REDOR的核磁共振重耦合实验直接测量。在对昆虫、贻贝和植物蛋白的研究中，具体的化学问题将回答这些结构是如何交联和稳定的。研究人员将寻找新的方法来稳定缓冲糖玻璃中脆弱的蛋白质复合物。这些基质将被用来检测被困在玻璃中的烯醇丙酮酰莽草酸3-磷酸合成酶的天然底物反应中间体。最后，通过将一个稳定的自由基埋在两亲性粒子的核心中来制造一种用于动态核极化实验的掺杂剂，该两亲性粒子可以使蛋白质和DNA复合。REDOR将用于表征局部结构，所得到的距离将作为分子动力学模拟的约束条件，用于可视化复合物的整体形状。许多生物化学和生物物理过程是由分子上层结构或在分子上层结构中进行的。这些超结构是大分子复合物或聚集体，它们没有原子水平的结构信息，因为它们不溶（没有溶液核磁共振），也不结晶（没有x射线晶体学）。这项工作将为重要的实际问题（害虫管理，船体藤条污染，酶反应途径，DNA压实）提供具体的见解，并产生一种具有原子水平分辨率的新型生物物理结构工具（固态核磁共振），适用于其他难以处理的系统。