Structure and Interactions of Gas Vesicles by SSNMR

通过 SSNMR 观察气体囊泡的结构和相互作用

• 批准号: 6742443
• 负责人: JUDITH HERZFELD
• 金额: $ 30.22万
• 依托单位: BRANDEIS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-05-01 至 2008-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6742443
• 关键词: Archaea; Halobacteriaceae; acidity /alkalinity; bacterial proteins; carbon; cell component structure /function; chemical models; gas; intermolecular interaction; membrane proteins; molecular biology; nitrogen; nuclear magnetic resonance spectroscopy; protein structure function; protonation; species difference; stable isotope; vesicle /vacuole

DESCRIPTION (provided by applicant): Despite great interest in their remarkable properties, and the considerable range of expertise brought to bear by several groups over many years, only the most general features of the structure of gas vesicles are known. However, recent developments now poise solid state NMR to provide numerous unique probes of the atomic details of the structure of the 7kDa monomer, gvpA, and its assembly into rigid, amyloid-like shells. Preliminary 13C and 15N spectra of uniformly labeled vesicles indicate that a combination of several isotope labeling strategies and an array of multidimensional correlation experiments should allow the full assignment of resonances and the determination of both intra-monomer and inter-monomer structural constraints. Ultimately, this information will allow the complete structure of the gas vesicle shell to be determined. Work will be carried out simultaneously on gas vesicles from the archae Halobacterium salinarum and the cyanobacterium Anabaena flos-aquaea. The parallel efforts will be synergistic because of the strong core homology between the gvpA's of the two species and the different isotope labeling strategies available in the two organisms. The parallel efforts will also be complimentary because of differences in overall vesicle morphology associated with differences in the N- and C-terminal domains of the two gvpA sequences. The role of electrostatics will be explored by identifying the cation displacements and protonation changes that induce vesicle collapse with decreasing pH. The response to salt will also be interesting since H. salinarum is a halophile and A. flos-aquaea is adapted to sweet water. Discovered structural details will shed light on the molecular basis of the morphology and rigidity of the vesicles, the prevention of water condensation within these gas permeable organelles, and the controlled assembly and disassembly of these amyloid-like aggregates.

描述（由申请人提供）：尽管人们对其显着的特性非常感兴趣，并且多年来多个小组提供了相当广泛的专业知识，但仅了解气体囊泡结构的最一般特征。然而，最近的发展使得固态核磁共振能够提供许多独特的探针，了解 7kDa 单体 gvpA 结构的原子细节，及其组装成刚性的淀粉样蛋白壳。均匀标记的囊泡的初步 13C 和 15N 光谱表明，几种同位素标记策略和一系列多维相关实验的组合应该允许共振的完全分配以及单体内和单体间结构约束的确定。最终，这些信息将允许确定气体囊泡壳的完整结构。将同时对古细菌盐杆菌和蓝藻鱼腥藻的气体囊泡进行研究。由于两个物种的 gvpA 之间具有很强的核心同源性以及两个生物体中可用的不同同位素标记策略，并行的努力将具有协同作用。由于总体囊泡形态的差异与两个 gvpA 序列的 N 端和 C 端结构域的差异相关，并行的努力也将是互补的。通过识别随着 pH 值降低引起囊泡塌陷的阳离子位移和质子化变化，我们将探讨静电的作用。对盐的反应也很有趣，因为 H. salinarum 是嗜盐生物，而 A. flos-aquaea 适应甜水。发现的结构细节将揭示囊泡形态和刚性的分子基础、防止这些透气细胞器内的水凝结，以及这些淀粉样蛋白聚集体的受控组装和分解。