Designing and Understanding High-performance Titin Polymers Using Synthetic Biology

非技术性描述：合成生物学提供了一种通过环境友好工艺从可再生原料（如生物质衍生糖）生产材料的新途径。此外，合成生物学可以更精确地控制材料特性。该项目将使用合成生物学来生产，表征和理解一种新型的基于蛋白质的纤维材料，称为titin聚合物，该材料将使用工程细菌从可再生原料中生产。该项目将提供目前未知的关于肌联蛋白聚合物的序列-性质关系的细节，这些细节可以指导未来高性能生物材料的设计。该项目还将从不同的蛋白质和生物来源中创造出多种新型聚合物，这些聚合物可能具有出色的机械性能。此外，该项目将作为使用合成生物学的关键概念验证，不仅可以生产生物材料，还可以了解生物材料的分子机制。所提出的合成生物学策略可用于研究许多其他类型的材料。本项目的目标是利用合成生物学的方法，设计、合成、表征和分析一种新型超高分子量（UHMW）肌联蛋白聚合物，以了解蛋白质序列与材料力学性能之间的关系。本项目的主要目的是研究肌联蛋白聚合物的结构与功能，为肌联蛋白聚合物的研究提供理论基础。该项目将使用合成生物学方法合成一系列具有不同但精确控制的单体的UHMW肌联蛋白聚合物（即，免疫球蛋白（IG）结构域）组成和顺序，以及在IG结构域的表面或核心残基上具有突变。将这些不同的UHMW肌联蛋白聚合物纺成纤维，并表征纤维的机械性能。通过分析由不同的titin聚合物制成的纤维的机械性能，该项目将揭示导致titin纤维的高拉伸强度、韧性和阻尼能的序列-性能关系。具体目标包括（1）理解Ig-IG相互作用对纤维强度和韧性的影响，（2）理解IG折叠能对纤维阻尼能的影响，和（3）从基因组数据库中探索新颖聚合物的多样性IG结构域。从这个项目中学到的知识将转化为设计规则，指导未来微生物生产的高性能titin纤维的工程设计，这些纤维具有可预测的性能，可用于广泛的应用。这个奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识价值和更广泛的影响审查标准进行评估来支持。

Non-technical description:Synthetic biology offers a new route of material production from renewable feedstock (such as biomass-derived sugars) through environmentally-friendly processes. Furthermore, synthetic biology enables more precise control over material properties. This project will use synthetic biology to produce, characterize, and understand a new type of protein-based fiber material, called titin polymers, that will be produced from renewable feedstock using engineered bacteria. This project will provide currently unknown details about sequence-property relationships in titin polymers that can guide design of future high-performance biomaterials. This project will also create multiple novel polymers from diverse protein and organism sources that may have outstanding mechanical properties. Additionally, this project will serve as a critical proof-of-concept for using synthetic biology to not only produce biomaterials but also understand the molecular mechanisms of biomaterials. The proposed synthetic biology strategy can be used to study many other types of materials. This project will also benefit society by creating new high-performance biomaterials that can potentially replace synthetic fibers made from petroleum feedstock, thus reducing CO2 emission and protecting the environments.Technical description:The goal of this project is to use this synthetic biology strategy to design, synthesize, characterize, and analyze a new type of ultra-high molecular weight (UHMW) titin polymers to understand the relationship between protein sequences and material mechanical properties. This project will use synthetic biology approaches to synthesize a series of UHMW titin polymers with different but precisely controlled monomer (i.e., immunoglobulin (Ig) domain) compositions and orders and with mutations on either the surface or core residues of the Ig domains. These different UHMW titin polymers will be spun into fibers, and fiber mechanical properties will be characterized. By analyzing the mechanical properties of fibers made from different titin polymers, this project will uncover the sequence-property relationships that give rise to the high tensile strength, toughness, and damping energy of the titin fibers. Specific aims include (1) understanding the effect of Ig-Ig interactions on fiber strength and toughness, (2) understanding the effect of Ig folding energy on fiber damping energy, and (3) exploring diverse Ig domains from genome database for novel polymers. Knowledge learned from this project will translate into design rules to guide future engineering of microbially-produced high-performance titin fibers with predictable properties for a broad range of applications.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.