CAREER: The Molecular Structure of Type II Collagen by Fiber Crystallography

摘要：胶原蛋白是重要的结构蛋白。它们构成了所有哺乳动物器官以及血管、皮肤、骨骼和软骨的基础结构。了解这些蛋白质如何相互作用，并受哺乳动物和人类正常生长、发育和修复过程的影响，需要了解胶原蛋白在自然状态下是如何组织的。一些结缔组织，例如主要由II型和I型胶原蛋白形成的结缔组织是天然结晶的，这一事实可以通过使用某些x射线衍射技术来有效地利用胶原蛋白的分子结构成像，同时保持样本组织的完整性。这个项目将建立在Orgel实验室的一些发展的基础上，这些发展以前被用来确定I型胶原蛋白的天然、完整的结构。该项目的第一个目标是应用这些衍射成像的创新来确定II型胶原蛋白的自然、完整的结构。由于II型胶原在生长发育中的关键作用，以及II型胶原与i型胶原之间的共同作用和相互作用，预计这样做将产生重大影响。该项目的第二个目标是通过以下方式推进“纤维晶体学”的发展领域：发展“大分子晶体学”的x射线衍射技术，优化样品的低温保存策略，开发微米级衍射方法，开展传播活动，培训学生和向当地社区进行教育宣传。这种集中的努力不仅会大大提高对纤维结缔组织分子结构的理解，而且会在纤维晶体学这一新兴领域取得实质性进展，其中包括培训人员和未来的科学家，他们有一天会成为这一领域和其他生物物理学科的实践者。更广泛的影响和推广：这个项目的影响是由首席研究员承担的领导角色加强。PI是美国晶体学协会纤维衍射特别兴趣小组（Fiber SIG）的当选主席，也是NSF支持的纤维衍射研究协作网络（RCN）的核心成员。这些作用支持并加强了他进行外联和传播本项目期间开展的活动的能力。作为生物物理协作访问团队设施（BioCAT）的光纤晶体学副主任，先进光子源（APS），阿贡，伊利诺伊州，PI负责光纤晶体学WAXS和微衍射仪器的技术开发以及这些领域科学界的发展。这项任务是为科学界开发高度优化的设施，这也将大大提高该项目成功的可能性，同时提供了一个科学领导的位置，他可以在那里传播他的发现，并促进对生物物理学科（包括纤维和大分子晶体学）的年轻科学家的培训和指导。这些活动与该项目特别具有协同作用，代表了国家科学基金会资源的重大杠杆作用。该项目的教育价值部分取决于研究阶段以离散模块组织的方式，以便让本科生和高中生与研究生，研究生和教师团队成员一起在垂直整合的研究团队中为研究项目做出切实的贡献。学生人员通过各种基于机构的项目或兼职研究助理从机构和周边地区（主要是低收入的非洲裔美国人和拉丁裔）招聘。后一种方法有助于培养“现实世界”的专业精神和奉献精神。

Summary: The collagens are important structural proteins. They form the infrastructure of all mammalian organs as well as blood vessels, skin, bones and cartilage. Understanding how these proteins interact and are affected by normal growth, developmental and repair processes in mammals, and therefore humans, requires knowledge of how collagen is organized in its natural state. Some connective tissues, such as those formed chiefly by type II and type I collagen are naturally crystalline, a fact that can be usefully exploited by using certain X-ray diffraction techniques to image the molecular structure of collagen whilst keeping the sample tissue intact. This project will build on a number of developments in the Orgel lab that were previously used to determine the natural, intact, structure of Type I collagen. The first goal of this project is to apply these innovations in diffraction imaging to determining the natural, intact, structure of type II collagen. It is expected that so doing will have significant impact, due to type II collagens key role in growth and development and the shared roles and interactions between collagen types II and I. The second goal of the project is to advance the developing field of "Fiber Crystallography" by: development of X-ray diffraction techniques adapted from "macromolecular crystallography", optimizing cryogenic-preservation strategies for samples, development of micrometer scale diffraction methods, engaging in dissemination activities, training of students and educational outreach to the local community. This focused effort should result, not only in a greatly improved understanding of the molecular architecture of fibrous connective tissue but also in substantial advances for the emerging field of fiber crystallography, which includes the training of personnel and future scientists who will one day become the practitioners of this and other biophysical disciplines.Broader impact and Outreach: The impact of this project is enhanced by leadership roles undertaken by the Principal Investigator. The PI is the chair-elect of the American Crystallographic Associations Fiber Diffraction Special Interest Group (Fiber SIG) and a core member of the NSF supported Fiber diffraction Research Collaborative Network (RCN). These roles support and enhance his ability to conduct outreach and dissemination of the activities conducted during this project. As Associate Director for Fiber Crystallography at the Biophysics Collaborative Access Team facility (BioCAT), Advanced Photon Source (APS), Argonne, IL, the PI is responsible for technical developments for fiber crystallography WAXS and micro-diffraction instruments and the development of the scientific community in these areas. This mandate, to develop highly optimized facilities for the scientific community, will also greatly enhance the probability of success of this project whilst providing a position of scientific leadership from which he can disseminate his findings, and facilitate the training and mentoring of young scientists in the biophysical disciplines (including fiber- and macromolecular crystallography). These activities are exceptionally synergistic with this project, representing a substantial leveraging of NSF resources. The educational value of this project partly rests with the way in which the research phases are organized in discrete modules, in order to allow undergraduate and high-school students to make tangible contributions to the research project alongside graduate, post-graduate and faculty team members in a vertically integrated research team. Student personnel are recruited from the institution and surrounding area (which is predominantly low-income African-American and Latino) through a variety of institution based programs or as part-time research assistants. The latter approach helps develop a sense of 'real-world' professionalism and dedication.