Anion Exchange in Bacteria

这项研究探讨了物理和细胞生物化学， 在革兰氏阴性厌氧菌中发现的一种新的交换蛋白 产草酸杆菌 在这种厌氧生物中， 二价草酸盐形成一价甲酸盐的基础， 质子动力的产生。 这种逆向反应是 在“化学渗透”载体中前所未有的作用， 细胞生物化学和独特的阴离子交换蛋白 因为它的产电特性 已经设计了测定以 在不丧失功能的情况下重建该反向转运反应， 用作从膜中纯化交换蛋白的指导 的O.产甲酸菌 蛋白质纯化后， 揭示动力学反应机理（乒乓或同时） 而反应循环中携带电荷的部分 膜。 使用残基特异性化学探针，单克隆 针对反向转运蛋白的抗体，以及衍生的 氨基酸序列的预测将作出有关的物理 结构 产草酸杆菌是一种革兰氏阴性厌氧菌， 代谢能量的唯一来源来自脱羧作用 草酸。 O. 产甲酸菌含有一种载体， 二价草酸盐和一价甲酸盐的交换。 这 反应是细胞生物化学特别感兴趣的， 生物体维持质子动力的机制。 因此，前体和产物的反向转运导致净 进入负电荷，而消耗质子期间， 草酸脱羧改变内部pH值。这是一种新的用途 对于这样的“第二”载波， 其他利用羧酸的细胞是否也利用 这种反向反应。 本研究将探讨 这种载体的分子特性及其在 细胞生物化学 这项工作将有助于目前 了解细菌如何组织其细胞功能。

This research examines the physical and cellular biochemistry of a novel exchange protein found in the gram-negative anaerobe Oxalobacter formigenes. In this anaerobe, the exchange of divalent oxalate for monovalent formate forms the basis for generation of proton-motive force. This antiport reaction is unprecedented among "chemiosmotic" carriers for its role in cellular biochemistry and unique among anion exchange proteins for its electrogenic character. Assays have been devised to reconstitute this antiport reaction without loss of function and are used as a guide to purify the exchange protein from membranes of O. formigenes. After the protein is purified experiments will reveal the kinetic reaction mechanism (Ping Pong or Simultaneous) and that portion of the reaction cycle which carries charge over the membrane. Using residue-specific chemical probes, monoclonal antibodies directed against the antiport protein, and the derived amino acid sequence predictions will be made about the physical structure. Oxalobacter formigenes, a gram-negative anaerobe, is a cell whose sole source of metabolic energy derives from the decarboxylation of oxalic acid. It has been established that membranes of O. formigenes contain a carrier that displays the electrogenic exchange of divalent oxalate and monovalent formate. This reaction is of particular interest to cellular biochemistry as a mechanism whereby the organism sustains a proton-motive force. Thus, the antiport of precursor and product results in the net entry of negative charge, while consumption of a proton during oxalate decarboxylation changes internal pH. This is a novel use for such a "secondary" carrier and is of interest to determine whether other cells that utilize carboxylic acids also exploit such antiport reactions. This research will examine the molecular properties of this carrier and its overall function in cellular biochemistry. This work will contribute to the current understanding of how bacteria organize their cellular functions.