Self-Assembly of Collagen-like Octadecamers Based on the Stem Region of C1q and Related Proteins

基于C1q茎区及相关蛋白的类胶原十八聚体自组装

• 批准号: 2203937
• 负责人: Jeffrey Hartgerink
• 金额: $ 45.52万
• 依托单位: William Marsh Rice University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2203937&HistoricalAwards=false
• 关键词: Self; Assembly; Collagen; like; Octadecamers

With the support of the Macromolecular, Supramolecular and Nanochemistry program in the Division of Chemistry, Professor Jeffrey D. Hartgerink of William Marsh Rice University is studying self-assembly of small popypeptides that structurally mimic collagen. Collagen is the most abundant protein in the human body and plays major roles in wound healing, tissue regeneration, cancer metastasis and the overall integrity of both soft and hard tissues. This protein is composed of three polypeptide chains that are wrapped together in a tight triple helix. Each polypeptide chain consists of sequences of amino acids that are linked by a particular kind of chemical bond called a peptide bond or link. When counting all amino acids, collagen is a very large macromolecule with molecular weight approaching 300,000 g/mol. This size limits the access to atomic level information about how the triple helix in collagen is assembled and formed in solution. To circumvent this problem, the research team will focus on smaller fragments from two different regions in collagen, namely “stem” where the six triple helices bundle together and the “branches” where the triple helices splay outward from one another making independent triple helices. Polypeptides chains from these two regions will be synthesized and thoroughly characterized using a suite of sophisticated chemical techniques. A computational algorithm SCEPTTr will be utilized to aid in the experimental design and identify the minimal sequences of amino acids needed for self-assembly. Diverse sequences of the branch region have the potential to provide well folded triple helical systems that will expand understanding of triple helix stabilization. The stem region, on the other hand, could offer opportunity to determine the atomic level structure of parallel packed triple helices. The research will provide an outstanding basis for undergraduate and graduate educational programs because it is multi-disciplinary in nature and combines chemical design and synthesis with traditional structural biology and medical application. Outreach programs will recruit high school students and their teachers in underserved communities to participate in research over the summer and develop exciting curriculum that integrates this work. SCEPTTr will be enhanced and continued to be distributed to the community with the aim to assist in the design of larger peptide mimics. This research will focus on the self-assembly of collagen-like octadecamers based on the stem region of C1q and related Defense Collagens. In the first objective, Collagen Mimetic Peptides (CMPs) with sequences taken from the branch region of Defense Collagens will be prepared. These chemically diverse sequences will be selected for self-assembly studies because they show a tendency to fold. Peptides will be prepared by solid phase peptide synthesis using standard Fmoc chemistry and characterized for their thermal stability. Key pairwise interactions will also be independently examined. This stability data will be used to improve the range of sequences accurately modeled by SCEPTTr. Biologically derived sequences will be stabilized through covalent capture and tested for their ability to bind known ligands of Defense Collagens. In the last objective, CMPs with sequences taken from the stem region of Defense Collagens will be synthesized and oligomerized to form octadecamers. A sequence study will be performed to assess the minimal regions required for octadecamer self-assembly. Well folded octadecamers will be further characterized by NMR and X-ray crystallography. Helical bundles will be stabilized by covalent capture and tested for their ability to bind relevant ligands. This project, if successful, will improve general understanding of the multi-step, hierarchical self-assembly of collagen and provide an assessment of CMPs for potential biomedical applications. In addition to the fundamental biophysical knowledge gained from this structural investigation, the critical role that Defense Collagens play in the innate immune response and the overall orchestration of inflammation and immunity will create many opportunities for preparing novel peptide-based drugs and biopolymers.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.

在化学系大分子、超分子和纳米化学项目的支持下，威廉·马什·赖斯大学的杰弗里·D·哈特林克教授正在研究结构上模仿胶原蛋白的小分子多肽的自组装。胶原蛋白是人体内含量最丰富的蛋白质，在伤口愈合、组织再生、肿瘤转移以及软硬组织的整体完整性等方面发挥着重要作用。这种蛋白质由三条多肽链组成，这些多肽链被紧密的三股螺旋缠绕在一起。每条多肽链由氨基酸序列组成，这些氨基酸通过一种特殊的化学键连接在一起，这种化学键被称为肽键或连接。当计算所有氨基酸时，胶原是一种非常大的大分子，其相对分子质量接近30万g/mol。这种大小限制了获取有关胶原蛋白中三螺旋如何在溶液中组装和形成的原子级信息。为了绕过这个问题，研究小组将专注于胶原蛋白中两个不同区域的较小片段，即六个三螺旋捆绑在一起的“茎”和三个螺旋相互向外张开形成独立三螺旋的“分支”。来自这两个区域的多肽链将被合成，并使用一套复杂的化学技术进行彻底的表征。计算算法SCEPTTr将被用来帮助实验设计和识别自组装所需的最小氨基酸序列。分支区域的不同序列有可能提供折叠良好的三螺旋系统，这将扩大对三螺旋稳定性的理解。另一方面，茎区域可以提供确定平行堆积三螺旋的原子级结构的机会。这项研究将为本科和研究生教育项目提供出色的基础，因为它是多学科的，将化学设计和合成与传统的结构生物学和医学应用相结合。外展计划将招募服务不足社区的高中生和他们的老师在夏季参与研究，并开发令人兴奋的课程，整合这项工作。SCEPTTr将得到加强，并继续分发给社区，目的是帮助设计更大的多肽模拟物。本研究的重点是基于C1q的茎区域的胶原样十八聚体的自组装以及相关的防御性胶原蛋白。在第一个目标中，将制备具有防御性胶原蛋白分支区域序列的胶原蛋白模拟肽(CMPS)。这些化学上不同的序列将被选择用于自组装研究，因为它们显示出折叠的趋势。将使用标准的Fmoc化学通过固相多肽合成来制备多肽，并对其热稳定性进行表征。还将独立审查关键的成对交互。该稳定性数据将用于改进SCEPTTr准确模拟的序列范围。生物衍生的序列将通过共价捕获来稳定，并测试它们与已知的防御性胶原蛋白配体结合的能力。在最后一个目标中，从国防胶原蛋白的茎区域中提取序列的CMPS将被合成并齐聚成十八聚体。将进行序列研究，以评估十八聚体自组装所需的最小区域。折叠良好的十八碳酸酯将进一步通过核磁共振和X射线结晶学进行表征。螺旋束将通过共价捕获来稳定，并测试它们结合相关配体的能力。如果该项目成功，将提高对胶原蛋白多步骤、分级自组装的总体理解，并为潜在的生物医学应用提供CMPS的评估。除了从这项结构研究中获得的基本生物物理知识外，防御性胶原蛋白在先天免疫反应以及炎症和免疫的整体协调中所发挥的关键作用将为制备新型多肽药物和生物聚合物创造许多机会。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。