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Joint Studies on Functional Role of Archaeal Macrocyclic Lipids

古菌大环脂质功能作用的联合研究

基本信息

批准号：
11694062
负责人：
EGUCHI Tadashi
金额：
$ 1.6万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11694062/
关键词：
Archaea Membrane Lipid Liposome Macrocyclic Lipid 物性

项目摘要

Archaea including methanogens, extreme halophiles, extreme thermophiles and thermoacidophiles grow under rather extraordinary conditions and have structurally unique membrane lipids to adapt the extreme environments. The lipids are consisted of hydrophobic isoprenoid chains linked to glycerol with the ether bonds, which are well contrast to the ester linkage of the eubacterial and eukaryotic membrane lipids. The most striking feature of the archaeal ether lipid is found in the macrocyclic (36-or72-membered) ring structures. These unusual lipids have been interested in connection with the physicochemical properties based on the lipid bilayer structure. Our interest in these lipids focuses on the biochemical significance of the macrocyclic molecular structures.Some biophysical properties of synthetic 36-membered archaeal phospholipids were studied using differential scanning calorimetry, electron and optical microscopies, stopped-flow/light scattering and solid-state ^2H-NMR techniques. … More This phospholipid gave a variety of self-organized structures in water, in particular vesucles and tubules. Some specific membrane properties of this archaeal phospholipid were observed : they are in a liquid-crystalline state over a wide temperature range ; the dynamics of their polyprenyl chains is higher than that of n-acyl chains ; the water permeability of the membranes is lower than that of n-acyl phosholipid membranes. It was also found that macrocyclization improves remarkably the barrier proprtlies to water and the membrane stability. This may be related to the adaptation of Methanococcus jannaschii to the extreme conditions of the deep-sea hydrothermal vents.Further, the self-assembly properties of 72-membered macrocyclic tetraether phosphates, the major phospholipid components of Sulfolobus, Thermoplasma and methanogenic Archaea, which were also synthesized, were observed by phase contrast and fluorescence. The 72-membered macrocyclic dipolar phosphates formed spontaneously vesicles. Less

古细菌包括产甲烷菌、极端嗜盐菌、极端嗜热菌和嗜热嗜酸菌，它们在相当特殊的条件下生长，并具有结构独特的膜脂以适应极端环境。脂质由通过醚键与甘油连接的疏水性类异戊二烯链组成，这与真细菌和真核细胞膜脂质的酯键形成鲜明对比。古菌醚脂质最显着的特征是在大环（36 或 72 元）环结构中发现的。人们对这些不寻常的脂质与基于脂质双层结构的理化性质的联系感兴趣。我们对这些脂质的兴趣集中在大环分子结构的生化意义上。使用差示扫描量热法、电子和光学显微镜、停流/光散射和固态 ^2H-NMR 技术研究了合成 36 元古细菌磷脂的一些生物物理性质。 … 更多这种磷脂在水中形成多种自组织结构，特别是囊泡和小管。观察到这种古菌磷脂的一些特定的膜特性：它们在很宽的温度范围内处于液晶状态；其聚异戊二烯链的动力学高于正酰基链；该膜的透水性低于n-酰基磷脂膜。还发现大环化显着改善了对水的阻隔性和膜稳定性。这可能与詹氏甲烷球菌对深海热液喷口极端条件的适应有关。此外，通过相差和对比观察了同样合成的硫化叶菌、热原体和产甲烷古菌的主要磷脂成分72元大环四醚磷酸酯的自组装特性。荧光。 72元大环偶极磷酸酯自发形成囊泡。较少的