OUTER MEMBRANE CYTOCHROMES--TOPOLOGY AND FUNCTION

描述：对厌氧呼吸有透彻的了解是非常重要的。 为了了解细菌的能量产生和生存与生长 人类和环境水库中的缺氧或缺氧环境。而当 许多细菌可以使用可溶性电子受体，腐烂希瓦氏杆菌 MR-1还可以使用高度不溶的底物(例如，氧化的锰或 铁)用于无氧呼吸。这种细菌有一种新的细胞色素 分布，将大多数结合在膜上的细胞色素定位到其外部 在厌氧生长条件下的膜(OM)，在那里他们可以 可能与细胞外不溶电子直接接触 接受者。 我们研究的长期目标是用这种细菌作为模型来 了解不溶物质的使用所涉及的电子传输系统 电子受体，这里特别强调OM的作用 细胞色素。我们建议需要一种或多种OM细胞色素 用于使用不溶性电子受体，以及其中一个或多个 细胞色素暴露在细胞表面(在那里它们可以直接 接触不溶的电子受体)。这样做的具体目的是 建议包括： 以确定使用不溶性是否需要OM细胞色素 电子受体，或其他厌氧呼吸过程。变种人 缺乏一种或多种OM细胞色素将被产生和研究 因为它们的无氧呼吸能力。我们会恢复这些变种人 与野生型DNA互补，然后重新检查它们的 电子传输能力。 测定细胞表面OM细胞色素的暴露量 厌氧生长的细胞。将使用多方面的方法，包括 细胞表面成分的免疫吸附、放射性碘标记和蛋白酶 敏感度研究。 这些研究将为一部小说提供必要的信息 产生能量的电子传输链似乎涉及 细胞质和外膜的成分；它们将扩大 目前将无氧呼吸视为一个过程的观点不仅限于 细胞膜和周质，但可以包括电子的细胞膜 通过组件中的组件传输到细胞外环境的链接 奥姆。这将大大提高我们对细菌生存的理解。 不同环境下的战略，并最终可能带来新的 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，为环境健康做出贡献 锰、铁和各种重金属的活化机制 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.