CAREER: The Statistical Mechanics of Filamentous Assemblies

职业：丝状组件的统计力学

• 批准号: 0955760
• 负责人: Gregory Grason
• 金额: $ 44.4万
• 依托单位: University of Massachusetts Amherst
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-01 至 2016-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0955760&HistoricalAwards=false
• 关键词: CAREER; Statistical; Mechanics; Filamentous; Assemblies

TECHNICAL SUMMARYThis CAREER award supports theoretical and computational research, and education on supermolecular assemblies of nanoscale filaments. Biofilaments present inherent challenges to theoretical study owing to the flexibility of the filaments themselves and the complexity of interactions among them. These effects are governed by long-wavelength physics, representing both soft deformations along filaments, as well as collective effects of inter-filament packing geometry.The PI will investigate the statistical and thermodynamic properties of filamentous assemblies that derive from the common structure of biological filaments. Namely, biofilaments are universally long, flexible and helical. The research addresses three aims: 1) establish the role of chirally-induced topological defects in finite-diameter bundle formation; 2) build a statistical theory of protein-mediated bundling of filamentous actin; and 3) explore the statistical mechanics of crystallization of pure and inhomogeneous filament assemblies.Project (1): The PI will establish a fundamental consequence of the geometric frustration between two dimensional and chirally ordered materials in the context of dense biofilament bundles. The PI will focus on the role played by disclinations that screen long-range stresses, which are themselves induced by chiral interactions between neighboring filaments. The PI aims to illuminate the influence of chirality on molecular assembly and provide insight into assembly mechanisms of biological filaments that are inherently limited in size. Project (2): The PI aims to construct a statistical mechanical framework, a coupled lattice-gas and lattice spin model, to explore the assembly thermodynamics of parallel actin bundles. The goal is to determine how an intrinsic frustration between the respective helical and six-fold symmetries of f-actin and bundle assemblies gives rise to cooperative binding of cross-linking proteins and influences bundle formation. Project (3): The PI will investigate the critical properties of filamentous systems as they pass through an unusually complex phase transition from two dimensional liquid-crystals to true three dimensional solids. The PI further aims to assess the role of quenched impurities inherent to crystallization of polydisperse filaments and expand our knowledge of the role of disorder in soft materials.The education component supports an effort to develop a new educational program that leverages existing center and faculty resources to create a Soft Matter Research in Theory summer program for undergraduate students. The program is designed to enhance the skills of students and enable them to participate in ongoing theoretical research projects. This program introduces students to the methods and challenges of modeling soft materials and the excitement of research in this area.NONTECHNICAL SUMMARYThis CAREER award supports theoretical and computational research, and education on assemblies of filaments composed of large molecules that have dimensions on scale of a nanometer ? a billionth of a meter. Filamentous assemblies like these are found inside biological cells and play an important role in giving them structural integrity. This award supports research to understand how filamentous assemblies organize themselves into more complex structures. This has important consequences for the structural and mechanical properties of filamentous assemblies. Aspects of the research will be done in collaboration with experimental efforts that use x-rays to study filament bundling in cells. The PI seeks to uncover fundamental principles that will also apply to the design of new synthetic materials that are structured on the nanometer scale.This research is an example of fundamental research in the mathematical and physical sciences at the boundaries with biology which has the potential to advance both.The education component supports an effort to develop a new educational program that leverages existing center and faculty resources to create a Soft Matter Research in Theory summer program for undergraduate students. The program is designed to enhance the skills of students and enable them to participate in ongoing theoretical research projects. This program introduces students to the methods and challenges of modeling soft materials and the excitement of research in this area.

该职业奖支持纳米级长丝的超分子组装的理论和计算研究以及教育。由于生物丝本身的灵活性和它们之间相互作用的复杂性，生物丝对理论研究提出了固有的挑战。这些效应是由长波物理控制的，代表了沿长丝的软变形，以及长丝间填充几何的集体效应。PI将研究源自生物细丝共同结构的丝状组件的统计和热力学性质。也就是说，生物丝普遍长，柔韧，呈螺旋状。本研究有三个目的：1)确定手性诱导的拓扑缺陷在有限直径束形成中的作用；2)建立蛋白介导的丝状肌动蛋白捆绑的统计理论；3)探索纯和非均匀细丝组合结晶的统计力学。项目(1):PI将在密集生物丝束的背景下建立二维和手性有序材料之间几何挫折的基本结果。PI将侧重于筛选远程应力的偏斜所起的作用，这些应力本身是由邻近细丝之间的手性相互作用引起的。该项目旨在阐明手性对分子组装的影响，并为生物细丝的组装机制提供见解，这些生物细丝本质上是有限的。项目(2)：该项目旨在构建一个统计力学框架，一个晶格-气体和晶格自旋耦合模型，探索平行肌动蛋白束的组装热力学。目的是确定f-肌动蛋白和束组装各自的螺旋和六重对称之间的内在挫折如何引起交联蛋白的合作结合并影响束的形成。项目(3):PI将研究丝状系统从二维液晶到真正的三维固体的异常复杂的相变过程中的关键特性。PI进一步旨在评估多分散细丝结晶中固有的淬火杂质的作用，并扩展我们对软材料中无序作用的认识。教育部分支持开发一个新的教育项目，利用现有的中心和教师资源，为本科生创建一个软物质理论研究暑期项目。该计划旨在提高学生的技能，使他们能够参与正在进行的理论研究项目。本课程向学生介绍建模软材料的方法和挑战，以及该领域研究的兴奋。这个职业奖支持理论和计算研究，以及关于由纳米尺度的大分子组成的长丝组装的教育。十亿分之一米。像这样的丝状组合存在于生物细胞内，在保证细胞结构完整性方面发挥着重要作用。该奖项支持研究了解丝状组装如何组织成更复杂的结构。这对丝状组件的结构和机械性能有重要的影响。这项研究的某些方面将与使用x射线研究细胞中纤维束的实验工作合作完成。PI旨在揭示基本原理，这些原理也将适用于纳米尺度结构的新型合成材料的设计。这项研究是数学和物理科学在生物学边界上的基础研究的一个例子，它有可能推动两者的发展。教育部分支持开发一个新的教育项目，利用现有的中心和教师资源，为本科生创建一个软物质理论研究暑期项目。该计划旨在提高学生的技能，使他们能够参与正在进行的理论研究项目。本课程向学生介绍建模软材料的方法和挑战，以及该领域研究的兴奋。