Membranes of Archaebacteria and Acidophilic Thiobacilli

这个项目探索了 嗜热嗜酸古细菌和嗜酸古细菌 硫杆菌 这些细菌生活在恶劣的环境中 包括低pH（2-4）和高温（50- 70 ℃）。 由于 这种环境的不寻常方面， 假设它们会有不寻常的膜， 使它们能够在极端的pH值和温度下存活。 事实上，已知古细菌作为一个群体 不是正常的酯脂质而是四醚脂质。 该提案的基础是， 这些细菌的细胞膜将提供脂质， 与真核生物不同的离子转运蛋白 膜。 这些差异将提供信息， 了解这些细菌的细胞生物学， 真核脂质的功能与离子转运 proteins. 该项目建议利用专业知识， 两个实验室来研究 这些细菌的细胞膜。 该项目包括两个 一个是史密斯博士的离子转运蛋白， 实验室和其他对脂质和脂质蛋白 在Chong博士的实验室中的相互作用如下所述。 分项目1：查明和描述 跨膜离子相关膜ATP酶 嗜酸性硫杆菌中的转运， 嗜热嗜酸古细菌 本次会议的目标- 项目是： 1.筛选不同菌株的膜 古细菌和嗜酸性硫杆菌形成离子 利用免疫学和酶的方法转移ATP酶 测定。 2.表征在特定的细胞中发现的ATP酶活性 目的1，关于抑制剂特异性，最适pH， 阳离子传输和动力学性质。 3.纯化一些与蛋白质相关的蛋白质， ATP酶活性见具体目标1和2。 重点将放在P型ATP酶。 次级项目2：物理特性 由四醚脂质组成的膜的性质 分离自嗜热嗜酸古细菌。 在这 次级项目： 1.将采用稳态和动态荧光测定法 研究芘标记脂质的横向运动 和二苯基己三烯（DPH）的旋转运动， 四醚脂膜中的二萘嵌苯。 2.小分子的横向和旋转运动 在四醚脂膜中作为压力的函数 将使用高压荧光测定法进行研究。 3.荧光测定法和常规生化方法将 用于古细菌（Na+，K+）- 型ATP酶。

This project explores the membranes of the thermoacidophilic archaebacteria and the acidophilic thiobacilli. These bacteria live in harsh environments including low pH (2-4) and high temperature (50-70C). Due to the unusual aspects of such environments it is hypothesized that they will have unusual membranes which allow them to survive at extremes of pH and temperature. In fact, it is known that the archaebacteria as a group do not have normal ester lipids but rather tetraether lipids. The foundation of the proposal is that the unusual nature of the membranes of these bacteria will provide lipids and ion transport proteins distinct from those in eukaryotic membranes. These differences will be informative in understanding both the cell biology of these bacteria and the function of eukaryotic lipids and ion transport proteins. This project proposes to use the expertise in two laboratories to study the lipids and proteins in the membranes of these bacteria. This project comprises two sub-projects, one on ion transport proteins in Dr. Smith's laboratory and the other on lipids and lipid protein interactions in Dr. Chong's laboratory as outlined below. Sub-project 1: Identification and characterization the membrane ATPases associated with transmembrane ion transport in acidophilic thiobacilli and thermoacidophilic archaebacteria. The goals of this sub- project are to: 1. Screen the membranes of various strains of archaebacteria and acidophilic thiobacilli for ion translocating ATPases using immunologic and enzymatic assays. 2. Characterize the ATPase activities found in specific aim 1, with regard to inhibitor specificity, pH optima, cation transport and kinetic properties. 3. Purify of some of the proteins associated with the ATPase activities described in specific aims 1 and 2. Particular emphasis will be placed on P-type ATPases. Sub-project 2: Characterization of the physical properties of membranes comprised of tetraether lipids isolated from thermoacidophilic archaebacteria. In this sub-project: 1. Steady-state and dynamic fluorometry will be employed to investigate the lateral motion of pyrene-labeled lipids and the rotational motion of diphenylhexatriene (DPH) and perylene in tetraether lipid membranes. 2. The lateral and rotational motions of small molecules in tetraether lipid membranes as a function of pressure will be studied using high pressure fluorometry. 3. Fluorometry and conventional biochemical methods will be used to study the topology of archaebacterial (Na+,K+)- type ATPase in tetraether lipid membranes.