Genome-Based Analysis of Methylotrophy

C1单位的产生、相互转化和转移是所有代谢系统中重要的基础代谢系统。 生物学许多生物合成反应都需要C1单元，此外， 在许多代谢反应中产生，必须解毒。甲基营养菌是微生物 能以C_2化合物为唯一碳源和能源生长， 作为所有生物体中存在的C_代谢的一种特殊形式。我们用基因组序列 的模式甲基营养菌，扭脱甲基杆菌AM 1在这个项目中产生的平台， 为同化和能量代谢如何实现动态平衡发展一个新的概念框架 在这个有机体中。我们建议开始用生物化学，遗传学， 基因组和建模方法。首先，我们将确定一个关键部分的剩余未知细节， 同化代谢，乙醛酸再生循环，特别是关于产生乙醛酸的步骤， 减少当量。这一目标解决的问题是， 甲基营养生长其次，我们将评估13-羟丁酰辅酶A的小分子调节剂， 两个主要同化途径之间的分支点，乙醛酸再生循环和PHB 合成.这一目标解决了这样一个问题，即什么信号参与了调节碳的流动， 主要的同化分支点。最后，我们将评估参与三个主要基因的表达。 在转录和酶活性水平的同化途径，并将此信息与 关键中间体和辅因子的细胞库的改变。这一目标解决了以下问题： 根据细胞需要，碳流在这些途径之间平衡。这项研究的结果将是一个 系统水平的理解中央同化代谢甲基营养。这些办法将 为生理水平的功能基因组学提供了一个模型，并将为未来的研究创造一个平台。 甲基营养同化和能量代谢的整合以及甲基营养同化和能量代谢之间的转换的研究 甲基营养和异养。

The production, interconversion, and transfer of C1 units is an important basic metabolic system in all of biology. C1 units are required for a number of biosynthetic reactions and in addition, formaldehyde is produced in a number of metabolic reactions and must be detoxified. Methylotrophs are microorganisms capable of growth on C_ compounds as sole carbon and energy sources, and methylotrophy can be viewed as a specialized version of the C_ metabolism found in all organisms. We have used the genome sequence of a model methylotroph, Methylobacterium extorquens AM1 generated in this project as a platform to develop a new conceptual framework for how assimilatory and energy metabolism achieve dynamic balance in this organism. We propose to begin to test this model using a combination of biochemical, genetic, genomic, and modeling approaches. First, we will determine the remaining unknown details of a key part of assimilatory metabolism, the glyoxylate regeneration cycle, especially with respect to the steps generating reducing equivalents. This aim addresses the question of how reducing equivalents are balanced during methylotrophic growth. Second, we will assess small molecule regulators of the 13-hydroxybutyryI-CoA branchpoint between two of the main assimilatory pathways, the glyoxylate regeneration cycle and PHB synthesis. This aim addresses the question of what signals are involved in regulating the flow of carbon at the main assimilatory branchpoint. Finally, we will assess expression of the genes involved in the three main assimilatory pathways at both transcript and enzyme activity levels and correlate this information with alterations in cellular pools of key intermediates and cofactors. This aim addresses the question of how carbon flow is balanced between these pathways according to cell needs. The result of this study will be a systems-level understanding of central assimilatory metabolism in methylotrophy. These approaches will provide a model for functional genomics at the physiological level, and will create a platform for future studies of the integration of methylotrophic assimilatory and energy metabolism and the switch between methylotrophy and heterotrophy.