OUTER MEMBRANE CYTOCHROMES--TOPOLOGY AND FUNCTION

描述：彻底了解无氧呼吸是必不可少的 了解细菌的能量产生、存活和生长， 人类和环境水库中的缺氧或hyosix环境。 而 许多细菌可以利用可溶性电子受体，腐败希瓦氏菌 MR-1还可以使用高度不溶性的底物（例如氧化的锰或锰氧化物）。 铁）用于无氧呼吸。 这种细菌有一种新的细胞色素 分布，将其膜结合的细胞色素定位于其外部 膜（OM）在厌氧生长条件下，在那里他们可以 潜在地与细胞外不溶性电子直接接触 受体。 我们研究的长期目标是以这种细菌为模型， 了解电子传输系统涉及使用不溶性 电子受体，这里特别强调OM的作用 细胞色素 我们认为，一个或多个OM细胞色素是必需的 对于不溶性电子受体的使用，并且这些受体中的一种或多种 细胞色素暴露在细胞表面（在那里它们可以直接 接触不溶性电子受体）。 具体目标是 建议如下： 为了确定使用不溶性染料是否需要OM细胞色素， 电子受体或其他厌氧呼吸过程。 的突变体 缺乏一种或多种OM细胞色素将被生成和研究 因为它们的无氧呼吸能力。 我们会让这些变种人 通过与野生型DNA互补将其转化为野生型，然后重新检查它们的 电子传输能力。 为了确定OM细胞色素的细胞表面暴露， 厌氧生长的细胞 将采用多方面的办法，包括 免疫吸附、细胞表面成分的放射性碘标记和蛋白酶 易感性研究 这些研究将为一部小说提供必要的信息。 产生能量的电子传递链， 细胞质和外膜的组成部分;他们将扩大 目前对无氧呼吸的认识不仅局限于 细胞质膜和周质，但其中可以包括电子 运输环节的细胞外环境，通过组件在 OM。 这将大大增强我们对细菌存活的理解 在不同的环境下的战略，并最终可能导致新的 控制或抑制细菌生长的策略。 他们还将 通过扩大我们对环境健康的了解， 锰、铁和各种重金属的动员机制 变成了供水系统。

DESCRIPTION: A thorough understanding of anaerobic respiraiton is essential to understanding bacterial energy generation and survival and growth in anoxic or hyosix environments in humans and environmental reservoirs. While many bacteria can use soluble electron acceptors, Shewanella putrefaciens MR-1 can also use highly insoluble substrates (e.g. oxidized manganese or iron) for anaerobic respiration. This bacterium has a novel cytochrome distribution, localizing most of its membrane-bound cytochromes to its outer membrane (OM) under anaerobic growth conditions, where they could potentially make direct contact with extracellular insoluble electron acceptors. The long-term goals of our research are to use this bacterium as a model to understand electron transport systems involved with the use of insoluble electron acceptors, with particular emphasis here on the role of OM cytochromes. We propose that one or more of the OM cytochromes are required for the use of insoluble electron acceptors, and that one or more of these cytochromes is exposed on the cell surface (where they could directly contact the insoluble electron acceptors). The specific aims of this proposal are: To determine if the OM cytochromes are required for the use of insoluble electron acceptors, or other anaerobic respiratory processes. Mutants that are deficient in one or more OM cytochromes will be generated and studied for their anaerobic respiratory capabilities. We will restore these mutants to wild-type by complementation with wild-type DNA and then re-examine their electron transport capabilities. To determine the cell surface exposure of the OM cytochromes in anaerobically grown cells. A multifaceted approach will be used, including immunoadsorption, radioiodination of cell surface components, and protease susceptibility studies. These studies will provide essential information on a novel energy-generating electron transport chain that appears to involve components of both the cytoplasmic and outer membrane; they will broaden the current vision of anaerobic respiration as a process not only confined to the cytoplasmic membrane and periplasm, but one which can include electron transport links to the extracellular environment through components in the OM. This will greatly enhance our understanding of bacterial survival strategies under diverse environments and could eventually lead to new strategies for controlling or inhibiting bacterial growth. They will also contribute to environmental health by expanding our knowledge on the mechanisms by which manganese, iron, and various heavy metals are mobilized into water supplies.