Defining glucan dikinase phosphorylation of starch from multiple kingdoms

淀粉在人类食品、农业动物饲料、生物燃料以及作为工业原料中发挥着核心作用。谷物和块茎中的淀粉占每日卡路里摄入量的50%-80%。在美国，36%的玉米被用作动物饲料，34%被转化为生物燃料。淀粉既是第一代生物燃料，也是微藻生产分子氢和石油的原料。它也是造纸、纺织品、粘合剂和塑料的工业原料。因此，需要确定控制淀粉代谢的途径，以开发新的策略来操纵这些途径，满足日益增长的淀粉需求。这个项目将定义从藻类到植物的分子能量储存机制，同时教学生使用生物信息学、生物物理学、结构生物学、细胞生物学和酶学来检验假设。该项目的更广泛影响可能会增加妇女和代表不足的少数民族在STEM中的参与，改善STEM教育和教育工作者的发展，帮助发展多样化和具有全球竞争力的STEM劳动力，并增加公众的科学素养和对科学技术的参与。淀粉葡萄糖的可逆磷酸化是唯一已知的淀粉的天然修饰，它直接影响淀粉的水化、结晶度、冻融稳定性、粘度和透明度，这些都是工业应用的核心。淀粉生产生物体拥有一种或两种葡聚糖双酶，可使淀粉葡萄糖磷酸化。它们的活性对体内淀粉的生产和利用至关重要。尽管它们具有重要的生物学作用，但人们对葡聚糖双激酶作用的物理和功能基础知之甚少。为了确定葡聚糖双键酶的生物学和生物化学，研究人员主要关注具有两个葡聚糖双键酶的绿色植物。此外，目前还没有办法利用它们独特的活动。这项研究将通过重点研究只拥有一个葡聚糖双激酶的藻类系统来开发利用葡聚糖双激酶的方法。该项目将最先进的生物物理方法与生物化学、细胞生物学、藻类遗传学和葡聚糖分析相结合，以确定葡聚糖双键酶的功能、动力学、结构和调节。这项研究的目的是：(I)确定葡聚糖双酶的分子酶学，(Ii)确定葡聚糖双酶的结构动力学和晶体结构，以及(Iii)阐明藻类葡聚糖磷酸化的生物学功能。该奖项由分子和细胞生物科学部、整合组织系统部和生命风险基金规则共同资助。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Starch plays a central role in human food, agricultural animals feed, biofuels, and as an industrial feedstock. Starch from cereal crops and tubers account for 50-80% of daily caloric intake. In the U.S., 36% of corn is dedicated to animal feed and 34% is converted into biofuels. Starch is both a first-generation biofuel and a feedstock for molecular hydrogen and oil production by micro-algae. It is also an industrial feedstock for paper, textiles, adhesives, and plastics. Therefore, defining the pathways that control starch metabolism is needed in order to develop novel strategies that manipulate these pathways and satisfy the growing starch demand. This project will define molecular energy storage mechanisms from algae to plants while teaching students to test hypotheses using bioinformatics, biophysics, structural biology, cell biology, and enzymology. The broader impacts of this project may increase participation of women and underrepresented minorities in STEM, improve STEM education and educator development, help develop a diverse and globally competitive STEM workforce, and increase public scientific literacy and engagement with science technology.Reversible phosphorylation of starch glucose is the only known natural modification of starch, and it directly influences starch hydration, crystallinity, freeze-thaw stability, viscosity, and transparency, which are all central to industrial applications. Starch producing organisms possess either one or two glucan dikinases that phosphorylate starch glucose. Their activity is critical for the production and utilization of starch in vivo. Despite their key biological role, little is known regarding the physical and functional basis for glucan dikinase action. To define the biology and biochemistry of glucan dikinases, the researchers focus on green plants which possess two glucan dikinases. Further, there is currently no means to harness their unique activity. This research will develop methods to utilize glucan dikinases by focusing on algal systems that possess only one glucan dikinase. The project combines state-of-the-art biophysical approaches with biochemistry, cell biology, algal genetics, and glucan analysis to define the function, dynamics, structures, and regulation of glucan dikinases. The objectives of this research are to: (I) define the molecular enzymology of glucan dikinases, (II) determine structural dynamics and crystal structures of glucan dikinases, and (III) elucidate the biological function of algal glucan phosphorylation.This award was co-funded by the Division of Molecular and Cellular Biosciences, the Division of Integrative Organismal Systems, and the Rules of Life Venture Fund.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.