Molecular Basis for Pre-Receptor Modulation of Plant Hormones by Acyl Acid Amido Synthetases

聪明的优秀人才需要对周围的环境和环境中的变化做出反应。作为这些反应的一部分，植物使用各种激素来改变它们的生长和新陈代谢，这些激素在化学上与动物中发现的激素无关。两种主要的植物激素是茉莉酸和生长素。这些分子的存在或不存在是由受体感知的，如果受体与激素结合，就会在植物中触发一种生物变化模式。这个项目的重点是GH3酶家族的蛋白质，它可以对激素进行化学修饰，以促进或阻止受体识别这些分子。GH3蛋白将不同的氨基酸结合到激素上，这可以导致产生活性分子，如茉莉酸，或产生非活性分子，如生长素。通过它们的生化活性，GH3蛋白可以控制受体的开启或关闭，并作为激素反应的受体前调节器。尽管GH3蛋白广泛存在于整个植物界，但人们对其生化功能知之甚少。该项目旨在通过X射线结晶学了解GH3蛋白的分子结构，研究GH3蛋白如何催化它们对不同化学成分的植物激素的反应，并深入了解每种GH3蛋白在植物激素反应中的生理作用。探索控制植物激素作用的分子基础将为植物生长、害虫防御和作物可持续发展所涉及的生化网络提供新的见解。例如，茉莉酸酯在改变与环境变化有关的各种化合物的新陈代谢、害虫/病原体防御以及生产用于生物燃料和工业原料的化合物方面至关重要。该项目还侧重于培训下一代多学科科学家。本项目所使用的研究方法和问题跨越了生物、化学和物理之间的界限，在实验室和教学中结合了X射线结晶学、生物化学和植物生物学。此外，对培养研究生更广泛的影响很大一部分集中在本科教育上。PI通过本科论文工作(Bio200、Bio500和Chem490)、华盛顿大学HHMI-SURF、CD-BioRAP(NSF-REU计划)和生物学和生物医学研究预科暑期学者计划积极招募本科生，并通过辉瑞-首诺夏季学生和教师研究科学家计划(STAR)指导高中生。PI是Bio4522：蛋白质生物化学实验室的课程硕士，并有在本科教学实验室课程中开发以研究为导向的项目的记录(Jez等人，2007生物化学。摩尔。比奥尔。电学。和Arkus&Amp；Jez，2008 Biochem。摩尔。比奥尔。教育)。Bio4522是一个以研究为导向的实验室，旨在让学生在研究的不同阶段取得进展，以检查科学问题并进行团队合作。2010年春季和2011年春季课程成功地为这项提议产生了一些关于拟南芥GH3蛋白质的初步数据，突显了这种方法对本科教育的价值。在这项提案的时间框架内，本课程的每一学期将专注于通过检查生命树中不同生物体的这些酶来研究GH3蛋白质功能在进化中的发展。

Intellectual MeritPlants need to respond to their surroundings and changes in their environment. As part of those responses, plants use various hormones, which are chemically unrelated to those found in animals, to alter their growth and change metabolism. Two major types of plant hormones are the jasmonates and auxins. The presence or absence of these molecules is sensed by receptors, which if bound to the hormone trigger a pattern of biological changes in the plant. This project focuses on proteins of GH3 enzyme family that chemically modify the hormones to either promote or prevent the receptor from recognizing these molecules. The GH3 proteins attach different amino acids to the hormone, which can lead to production of an active molecule, as occurs with jasmonates, or an inactive molecule, as with the auxins. Through their biochemical activity, the GH3 proteins can control if the receptor is on or off and act as pre-receptor modulators of hormone responses in plants. Although the GH3 proteins are widespread across the plant kingdom, little is known about their biochemical function. This project aims to understand the molecular structure of the GH3 proteins by using x-ray crystallography, to investigate how the GH3 proteins catalyze their reactions on chemically diverse plant hormones, and to provide insight on the physiological roles of each GH3 protein in plant hormone responses.Broader ImpactExploring the molecular foundations for control of plant hormone action will provide new insight on the biochemical networks involved in allocating resources for plant growth, pest defenses, and crop sustainability. For example, jasmonates are critical in altering metabolism of various compounds related to environmental changes, pest/pathogen defenses, and production of compounds useful for biofuels and industrial feedstocks. The project also focuses on training the next generation of multidisciplinary scientists. The research methods and questions used in this project cross the boundaries between biology, chemistry, and physics by integrating x-ray crystallography, biochemistry, and plant biology in both the lab and in teaching. In addition, to training graduate students a large portion of the broader impact efforts focus on undergraduate education. The PI actively recruits undergraduate students through undergraduate thesis work (Bio200, Bio500, and Chem490), the Washington U. HHMI-SURF, CD-BioRAP (an NSF-REU program), and the pre-freshman Summer Scholars in Biology and Biomedical Research program, and mentors high school students through the Pfizer-Solutia Summer Students and Teachers as Research Scientists (STARS) program. The PI is course-master for Bio4522: Protein Biochemistry Lab and has a record of developing research-oriented projects in undergraduate teaching lab courses (Jez et al., 2007 Biochem. Mol. Biol. Educ. and Arkus & Jez, 2008 Biochem. Mol. Biol. Educ.). Bio4522 is a research-oriented lab designed to have students progress through different stages of research to examine a scientific question and to work as a team. The success of the Spring 2010 & 2011 classes in generating some of the preliminary data on the Arabidopsis GH3 proteins for this proposal highlights the value of this approach for undergraduate education. During the timeframe of this proposal, each semester of the course will focus on investigating the development of GH3 protein function across evolution by examining these enzymes from different organisms in the Tree of Life.