Collaborative Research: Designing biomaterials through computational simulation and manipulation of phase behavior in a class of intrinsically disordered proteins

非技术概述缺乏明确结构的蛋白质在生物学和材料中扮演着许多重要的角色，从细胞内部分子的组织到弹性材料的产生，这些蛋白质发挥着从细胞内部分子组织到弹性材料的功能，这些弹性材料可以伸展到原始长度的数倍而不会永久变形。尽管这些类型的蛋白质具有广泛的用途，但对定义其性质的分子特征的详细了解仍处于起步阶段，这限制了它们在高性能生物材料中的应用。这项建议通过开发计算和实验方法来解决这一差距，这些方法将描述蛋白质的组成及其溶液的性质如何提供用于制造图案化弹性体基质的手柄，从长远来看，这将解决关键的社会挑战，如设计生物材料、控制生物分子的放置以实现化学功能，和/或更有效的能量存储。该项目的研究还将影响不同年龄和经历的学生的教育活动。PI将参与的一系列学生发起的活动和播客将有助于将该项目的概念转化为中学课程和实践经验。技术概述两种不同溶液的液-液相分离(LLP)是一种基本的热力学过程，在先进材料的开发和无膜细胞器(如核仁)的组装中具有重要意义。如果更详细地了解多肽链及其溶液的选定特征如何驱动IDPs中相分离的热力学和动力学，那么使用蛋白质LLP有目的地设计新材料可能会有显著的进步。因此，这项提议的首要目标是利用研究人员在计算机建模和重组设计类Resilin IDPs(RLP)方面的独特能力来设计在中尺度上显示可调材料性质的蛋白质凝聚体。该项目将利用闭环形式，结合对蛋白质LLP的最新模拟和RLP的广泛实验表征，提供关于氨基酸组成、序列和共溶质(盐或聚乙二醇)在LLP中的作用的迭代反馈。实验确定的选定RLP的第二维里系数的变化及其与计算的匹配(或偏差)将使计算方法能够进行微调。详细的光谱和散射表征将能够与计算预测相关联，并进一步确定凝聚体浓度和组成在水凝胶形态和性质中的作用。综上所述，这些研究将加深对国内流离失所者有限合伙人热力学和动力学的基本了解，并将允许前所未有地控制凝析油的设计，将微观结构和组成作为生物材料设计的元素。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。

Nontechnical SummaryProteins that lack defined structures play many important roles in biology and in materials, mediating functions from the organization of molecules in the interior of cells to the production of elastomeric materials that can stretch multiple times their original length without permanent deformation. Despite the widespread utility of these types of proteins, detailed understanding of the molecular features that define their properties is still just emerging, which has limited their application in high-performance biomaterials. This proposal addresses this gap by developing computational and experimental methods that will describe how the composition of the proteins and the properties of their solutions can provide handles for making patterned elastomeric matrices, which in the long term will address critical societal challenges such as engineering living materials, controlling placement of biomolecules to conduct chemical functions, and/or more efficient energy storage. The research in this program will also impact educational activities for students of a variety of ages and experience. A series of student-initiated activities and podcasts, in which the PIs will participate, will help transfer concepts of this program into secondary school curricula and hands-on experiences.Technical summaryLiquid-liquid phase separation (LLPS) of two dissimilar solutions is a fundamental thermodynamic process with significant importance in the development of advanced materials and for the assembly of membraneless organelles such as the nucleolus. The use of protein LLPS to purposefully design new materials could be significantly advanced if finer details were known about how select features of the polypeptide chain and its solutions drive the thermodynamics and kinetics of phase separation in the IDPs. The overarching goal of this proposal, accordingly, is to leverage unique capabilities of the investigators in computer modeling and recombinant design of resilin-like IDPs (RLPs) to design protein coacervates that display tunable material properties at the mesoscale. The project will leverage a closed-loop format, combining state-of-the-art simulations of protein LLPS alongside extensive experimental characterization of RLPs to provide iterative feedback about the role of amino acid composition, sequence, and co-solutes (salt or PEG) in LLPS. Variations in the experimentally determined second virial coefficients for selected RLPs, and their match (or deviation) from computation will enable fine-tuning of computational methods. Detailed spectroscopy and scattering characterization will enable correlation with computational prediction and further serve to establish the roles of coacervate concentration and composition in hydrogel morphology and properties. Taken together, these studies will deepen fundamental understanding of thermodynamics and kinetics of the LLPS of IDPs and will allow for unprecedented control over the design of condensates with controlled microstructure and composition as elements in biomaterials design.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.