"LiT": Regulation of 5-Aminolevulinic Acid Biosynthesis in the Bacterium Rhodobacter sphaeroides

该奖项是根据2009年美国复苏和再投资法案（公法111-15）资助的。智力meritripyrroles是所有生物体新陈代谢所需的基本生物分子。它们形成血红素部分的基础，血红素部分在产生能量的电子转移反应中起作用，并且它们还形成叶绿素的核心，叶绿素在光合作用中执行主要的捕光功能。因此，四吡咯对于生命系统中的能量转换是不可或缺的。该研究探讨了四吡咯生物合成中的重要步骤，即前体分子5-氨基乙酰丙酸（ALA）的生物合成。两个ALA合酶基因，hemA和hemT的活性和调节将在细菌Rhodobacter sphaeroides中进行研究，该细菌能够收获化学能和光能，并且可以固定碳和氮，所有过程都需要四吡咯。使用不同的代谢程序生长的能力使这种生物体能够最佳地利用环境资源，并且毫不奇怪，它的代谢响应于环境而被精细地调节。拟议的研究将调查hemA和hemT的调节，包括新型sigma因子SigT的作用，该因子参与hemT的转录。将测试这两种不同的ALA脱氢酶的存在的意义，因为它们与生长条件有关。实验涉及基本的细菌分子遗传学和生物化学。拟议的研究将为生物如何利用遗传灵活性来适应不同的环境提供新的见解。此外，还将获得有关基因表达调控和代谢途径的基本信息，这无疑对地球上生命的进化至关重要。sphaeroides的有氧生长与光合生长提供了一个非常令人信服的证明特定的基因调控。这些视觉上可观察到的代谢变化对环境的反应继续激起学生的好奇心和兴趣。超过38名学生，其中绝大多数是女性，曾在实验室工作，在那里他们学到了第一手资料，为什么基础研究是重要的和有价值的;几乎所有人都留在科学，毫无疑问，可以从拟议的调查中出现更广泛的成果。对这项研究的支持将仍然是优质课堂和实验室教学的基石;学生们自我报告说，他们熟悉最先进的科学，使他们在研究生和专业课程中更具竞争力。ALA具有农业和医疗用途。通过不产氧光养生物经济地生产它多年来一直受到全世界的关注。更清楚地了解其受调控的形成和所涉及的酶，以及这些细胞中的能量代谢，已经并将继续消除现有的障碍，以改善其生产。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-15).Intellectual meritTetrapyrroles are essential biomolecules required for metabolism in all organisms. They form the basis of heme moieties, which act in energy-generating electron transfer reactions, and they also form the core of chlorophylls, which perform the major light harvesting function in photosynthesis. Thus, tetrapyrroles are indispensable for energy transformations in living systems. The proposed research investigates an important step in tetrapyrrole biosynthesis, the biosynthesis of the precursor molecule 5-aminolevulinic acid (ALA). The activity and regulation of two ALA synthase genes, hemA and hemT will be studied in the bacterium Rhodobacter sphaeroides, which is capable of harvesting both chemical and light energy and can fix both carbon and nitrogen, all processes which require tetrapyrroles. The ability to grow using distinct metabolic programs allows this organism to optimally utilize environmental resources, and not surprisingly its metabolism is exquisitely regulated in response to the environment. The proposed research will investigate regulation of hemA and hemT, including the role of novel sigma factor SigT, which is involved in hemT transcription. The significance of the presence of these two different ALA synthases as they relate to growth conditions will be tested. Experiments involve basic bacterial molecular genetics and biochemistry. The proposed studies will provide new insights into how organisms use genetic flexibility to adapt to different environments. In addition, fundamental information will be gained about regulation of gene expression and metabolism of a pathway that no doubt has been critical to the evolution of life on earth.Broader ImpactsThe difference in color of R. sphaeroides growing aerobically vs. photosynthetically provides an extraordinarily convincing demonstration of specific gene regulation. These visually observable metabolic changes in response to the environment continue to pique the curiosity and interest students. Over 38 students, the vast majority of whom are women, have worked in the lab where they have learned first-hand why basic research is important and worthwhile; nearly all have remained in science, leaving no doubt of the broader outcomes that can emerge from the proposed investigations. Support for this research will remain a cornerstone to quality classroom and lab instruction; students have self-reported being acquainted with state-of-the-art science made them more competitive for graduate and professional programs. ALA has agricultural and medical uses. Its economical production by anoxygenic phototrophic organisms has been of interest throughout the world for many years. A clearer understanding of its regulated formation and the enzymes involved, as well as energy metabolism in these cells, has and will continue to remove existing impediments to improvements in its production.