Membrane Protein Folding

存在于细胞膜内的蛋白质是许多重要生命过程的核心，包括光合作用，呼吸和免疫反应。为了使蛋白质正常发挥功能，它必须折叠成特定的三维（3-D）形状或结构。化学部的生命过程化学项目正在资助朱迪·E·来自圣地亚哥加州大学的Kim博士研究了膜蛋白最重要和最具挑战性的方面之一，即它们折叠成正确的3-D结构。错误折叠的蛋白质会导致疾病，如阿尔茨海默氏症和囊性纤维化。这项研究的重点是了解一组膜蛋白（OmpA和OmpT）的折叠，以更好地了解这些蛋白质如何在细菌中组装。虽然建立膜蛋白的三维结构仍然是结构生物学的一个巨大挑战，但建立这些和其他蛋白质的折叠途径尤其具有挑战性。这项研究最重要的目标之一是更好地了解膜蛋白与其局部环境之间的相互作用如何影响折叠。将利用最先进的生物物理技术来解决这个问题。 参与该项目的本科生和研究生接受培训，成为化学/生物学界面的熟练研究人员，同时培养其他重要的职业技能，如沟通和领导力。这一项目的一个组成部分是开展外联活动，以帮助扩大对科学的参与。暑期培训计划，为蛋白质实验室实验（PURPLE）准备本科研究人员，将为来自服务不足社区的早期大学生提供基本的研究技能，致力于提高STEM的多样性。该培训计划和研究与生命系统生物学的强大转化联系使该项目非常适合在早期阶段激发本科生探索科学研究。这个跨学科项目的重点是折叠的两个β桶膜蛋白，OmpA和OmpT。其动机是获得一个更完整的了解脱水过程和天然伴侣蛋白在膜插入过程中的作用和这些膜蛋白的折叠。主要工具包括稳态和时间分辨电子和振动光谱，报告蛋白质结构的细节和折叠过程中局部环境的变化。将产生涉及色氨酸残基明智放置的各种靶向蛋白质突变体。 利用这些色氨酸残基作为光谱报告发色团，以阐明这些残基与其环境之间的特定相互作用。该项目的结果有望推动膜蛋白动力学和折叠领域的知识和理解。此外，这里采取的生物物理方法和这些研究的实验结果可能有助于核蛋白质动力学在其他复杂的生物assemblies.This奖项的补充理论和实验研究反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

Proteins that reside within cellular membranes are at the heart of many important life processes, including photosynthesis, respiration, and immune responses. For a protein to function properly, it must fold into a specific three-dimensional (3-D) shape or structure. The Chemistry of Life Processes Program in the Chemistry Division is funding Dr. Judy E. Kim from the University of California at San Diego to investigate one of the most important and challenging aspects of membrane proteins, their folding into correct 3-D structures. Incorrectly folded proteins can cause diseases, such as Alzheimer’s and cystic fibrosis. This research study focuses on understanding the folding of a set of membrane proteins (OmpA and OmpT) to better understand how these proteins assemble in bacteria. While establishing the 3-D structures of membrane proteins remains a grand challenge of structural biology, establishing the folding pathways for these and other proteins is especially challenging. One of the most important goals of this research is to better understand how interactions between the membrane protein and its local environment impact folding. State-of-the-art biophysical techniques will be brought to bear on this problem. Undergraduate and graduate students involved with the project are trained to become skilled researchers at the chemistry/biology interface, while building other important career skills such as communication and leadership. An integral part of this project involves outreach to help broaden participation in the sciences. A summer training program, Preparing Undergraduate Researchers for Protein Lab Experiments (PURPLE), will provide basic research skills to early-stage college students from underserved communities in a committed effort to enhance diversity in STEM. This training program and strong translational connections of the research to the biology of living systems make the project well-suited to inspire undergraduates at an early stage to explore scientific research. This interdisciplinary project focuses on the folding of two beta-barrel integral membrane proteins, OmpA and OmpT. The motivation is to gain a more complete understanding of the dehydration process and the role of a native chaperone protein during the membrane insertion process and the folding of these membrane proteins. The primary tools include steady-state and time-resolved electronic and vibrational spectroscopy that report on details of the protein structure and changes in the local environment during folding. Various targeted protein mutants involving the judicious placement of tryptophan residues will be generated. These tryptophan residues are exploited as spectroscopic reporting chromophores to elucidate specific interactions between these residues and their environment. Results from this project are expected to advance knowledge and understanding in the fields of membrane protein dynamics and folding. Additionally, the biophysical approaches taken here and the experimental findings of these studies may serve to nucleate complementary theoretical and experimental studies of protein dynamics in other complex biological assemblies.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.