ANALYSIS OF POLYHYDROXYALKANOATE INCLUSION BIOGENESIS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 本研究的目的是阐明聚羟基烷酸包合物的生物发生机制。聚羟基烷酸酯(PHAs)是一种细菌聚合物，在碳水平高而另一种基本营养物质(如氮)有限的情况下，在包裹体中合成。PHA有相当大的商业利益，因为它们由一系列聚酯组成，可以形成可生物降解的塑料。电子显微镜研究一直无法解析PHA包裹体的结构，这阻碍了包裹体生物发生的内聚模型的发展。利用原子力显微镜，我们确定了它有三层结构，外层是膜双层的厚度，中间网状层，和下面的晶片层。遗传学研究表明，中间网络至少部分由Phap组成，Phap很可能被移位到周质。因此，似乎可以通过蛋白质和/或蛋白质移动到周质并通过细胞质膜发芽进入细胞质，促进细胞质膜作为包膜的获得，从而发生包涵体生物发生。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The goal of this research is to elucidate the mechanism of polyhydroxyalkanoate inclusion biogenesis. Polyhydroxyalkanoates (PHAs) are bacterial polymers that are synthesized in inclusions when carbon levels are high and another essential nutrient, such as nitrogen is limited. There is considerable commercial interest in PHAs because they comprise a family of polyesters that can be formed into plastics that are biodegradable. Electron microscopy studies have been unable to resolve the structure of PHA inclusions and this has inhibited movement toward a cohesive model of inclusion biogenesis. Employing atomic force microscopy, we have determined that there are three layers of structure, an outer envelope that is the thickness of a membrane bilayer, a middle network layer, and an underlying crystalline lamellar layer. Genetic studies have indicated that the middle network is comprised at least partially of PhaP and that PhaP is likely to be translocated to the periplasm. Thus, it would appear that inclusion biogenesis may occur by movement of protein and/or proteins to the periplasm and budding through the cytoplasmic membrane into the cytoplasm, facilitating the acquisition of the cytoplasmic membrane as an envelope.