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: 6601244
• 负责人: JUDITH HERZFELD
• 金额: $ 30.12万
• 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/6601244
• 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)：尽管人们对气泡的非凡特性非常感兴趣，而且几个小组多年来带来了相当广泛的专业知识，但人们只知道气泡结构的最一般特征。然而，最近的发展使固体核磁共振能够为7 kDa单体gvpA的结构及其组装成刚性的淀粉样壳的原子细节提供大量独特的探针。均匀标记的囊泡的初步13C和15N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充分指定共振并确定单体内和单体间的结构限制。最终，这些信息将使我们能够确定气泡外壳的完整结构。将同时对古盐生盐生细菌和蓝藻水华鱼腥藻的气囊进行研究。平行的努力将是协同的，因为这两个物种的gvpA之间有很强的核心同源性，以及两个生物中可用的不同同位素标记策略。由于两个gvpA序列的N-末端和C-末端结构域在整体囊泡形态上的不同，并行的努力也将是互补的。静电学的作用将通过识别阳离子位移和质子化变化来探索，这些变化会随着pH的降低而导致囊泡崩溃。对盐的反应也将是有趣的，因为盐藻是一种嗜盐生物，而花藻则适应甜水。已发现的结构细节将揭示囊泡的形态和刚性的分子基础，防止这些透气细胞器内的水凝结，以及这些淀粉样聚集体的受控组装和拆解。