Probing the Molecular Structure and Dynamics of Spider Silk Proteins

ID: MPS/DMR/BMAT(7623) 1264801 PI: Yarger， Jeffrey ORG：亚利桑那州立大学标题：探测蜘蛛丝蛋白的分子结构和动力学技术：蜘蛛产生各种蛋白质，这些蛋白质被拉入具有机械性能的丝纤维中，可以胜过其他天然和合成纤维。对这些纤维的物理性质的完整分子水平的理解尚未实现。纤维包含一套复杂的二级蛋白质结构和纳米晶体结构域。PI将探索主要和次要壶形丝蛋白（拖丝和织网），圆柱形丝蛋白（也称为管状，用于卵壳）和腺状丝蛋白（猎物包裹）的分子结构和蛋白质动力学。最终目标是建立几种不同蜘蛛（包括圆织蜘蛛（Nephila and Argiope）和织网蜘蛛（Latrodectus hesperus））的各种天然丝蛋白的结构特征和机械功能之间的关系。分子结构的解析将主要使用多维固态核磁共振（ssNMR）技术进行。使用13C， 15N和1,2h同位素富集的蚕丝将允许2D/3D碳和氮同核和异核NMR实验来确定广泛的贯穿键和贯穿空间相关性。这些技术，连同超快魔角纺丝（MAS）和先进的1H同核解耦技术，将允许蜘蛛丝光谱的完整分配，并阐明这些生物聚合物中的所有二级结构元素。利用光纤x射线和中子衍射得到的对分布函数（PDF）将进一步用于表征取向蛛丝纤维中的纳米结构和短程非晶结构。PI还将开发和使用2H/13C二维核磁共振技术来询问蜘蛛丝蛋白的分子动力学。综上所述，这些研究将对天然蜘蛛丝纤维的分子结构和动力学产生前所未有的详细程度。非技术：蜘蛛生产各种蛋白质聚合物，我们称之为丝。在分子水平上理解丝绸对于利用这种材料和逆向工程其特性至关重要。在人造蛋白质基材料中复制蜘蛛丝特性的能力是在“现实世界”应用中使用这些高性能生物聚合物的关键。这个过程的第一步是向工程师提供有关天然材料结构和动力学的分子水平的详细信息，以便在重组或合成结构中复制这些信息。该项目将对几种天然蜘蛛丝的结构设计产生新的认识。上述目标的实现将提供新的方法来确定蛋白质纤维结构，并将这些结构与机械性能联系起来，同时为学生提供分子结构分析方面的广泛培训。这些研究项目将涉及一个由研究生、本科生和高中生组成的学生研究小组。研究小组将在亚利桑那州立大学和阿贡国家实验室接触科学研究和仪器。该研究小组还将参加美国国家科学基金会赞助的K-12教师暑期研究项目，并将为当地K-12学校提供蜘蛛丝研究的示范。将特别强调向代表性不足的西班牙裔和印第安人学校和社区提供服务。

ID: MPS/DMR/BMAT(7623) 1264801 PI: Yarger, Jeffrey ORG: Arizona State UniversityTitle: Probing the Molecular Structure and Dynamics of Spider Silk Proteins Technical: Spiders produce a variety of proteins, which are pulled into silk fibers possessing mechanical properties that can outperform other natural and synthetic fibers. A full molecular level understanding of the physical properties of these fibers has not yet been achieved. The fibers contain a complex set of secondary protein structures and nanocrystalline domains. The PI will explore the molecular structure and protein-protein dynamics of major and minor ampullate silk proteins (dragline and web-building), cylindrical silk proteins (also named tubuliform, used for egg case) and aciniform silk proteins (prey wrapping). The ultimate goal is to establish relationships between structural features and mechanical function in a variety of natural silk proteins from several different spiders, including orb-weaving (Nephila and Argiope) and cobweaving (Latrodectus hesperus) spiders. Elucidation of molecular structure will primarily be carried out using multidimensional solid-state NMR (ssNMR) techniques. Use of 13C, 15N and 1,2H isotopically enriched silks will allow 2D/3D carbon and nitrogen homo- and heternuclear NMR experiments to determine extensive through-bond and through-space correlations. These techniques, along with ultrafast magic angle spinning (MAS) and advanced 1H homonuclear decoupling, should allow for complete assignment of spider silk spectra and elucidate all secondary structure elements in these biopolymers. Pair distribution functions (PDF) obtained from fiber x-ray and neutron diffraction will further be developed to characterize the nano-structures and short-range amorphous structures in oriented spider silk fibers. The PI will also develop and use 2H/13C 2D NMR techniques to interrogate molecular dynamics of spider silk proteins. Taken together, these studies should produce an unprecedented level of detail regarding the molecular structure and dynamics of natural spider silk fibers.Non-Technical: Spiders produce various protein-based polymers that we call silk. Understanding silk at a molecular level is critical to utilizing this material and reverse engineering its properties. The ability to duplicate spider silk properties in man-made protein-based materials is the key to using these high-performance biopolymers in 'real-world' applications. A first step in this process is giving engineers the molecular level detailed information about the structure and dynamics in the natural material in order to reproduce this in recombinant or synthetic constructs. The proposed project will develop new understandings into the structural design of several natural spider silks. Accomplishment of the objectives outlined above will provide new methodologies to determine protein fiber structures and correlate these structures with mechanical properties as well as provide broad training in molecular structure analysis to students. These research projects will involve a student research team consisting of graduate, undergraduate, and high-school students. The research team will be exposed to scientific research and instrumentation at both Arizona State University and Argonne National Laboratory. The research group will also participate in NSF sponsored K-12 teacher summer research programs and will provide demonstrations of spider silk research to local area K-12 schools. Specific emphasis will be placed on outreach to underrepresented Hispanic and Native American schools and neighborhoods.