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.

技术摘要该职业奖支持理论和计算研究以及纳米级细丝超分子组装体的教育。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。这些效应受长波长物理控制，代表沿丝的软变形，以及丝间堆积几何形状的集体效应。PI 将研究源自生物丝常见结构的丝状组件的统计和热力学特性。也就是说，生物丝普遍都是长的、柔韧的和螺旋状的。该研究致力于三个目标：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）建立蛋白质介导的丝状肌动蛋白成束的统计理论； 3）探索纯和非均质丝组件结晶的统计力学。项目（1）：PI将在致密生物丝束的背景下建立二维和手性有序材料之间几何挫败的基本结果。 PI 将重点关注向错所起的作用，以筛选长程应力，这些应力本身是由相邻细丝之间的手性相互作用引起的。该 PI 旨在阐明手性对分子组装的影响，并深入了解尺寸本质上有限的生物丝的组装机制。项目（2）：课题负责人旨在构建一个统计力学框架，一个耦合的晶格-气体和晶格自旋模型，以探索平行肌动蛋白束的组装热力学。目标是确定 f-肌动蛋白和束组件各自的螺旋对称性和六重对称性之间的内在挫败如何引起交联蛋白的协同结合并影响束形成。项目 (3)：PI 将研究丝状系统在经历从二维液晶到真正的三维固体的异常复杂的相变时的关键特性。该 PI 进一步旨在评估多分散长丝结晶所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了解。教育部分支持开发一项新的教育计划，该计划利用现有的中心和教师资源，为本科生创建软物质理论研究夏季计划。该计划旨在提高学生的技能，并使他们能够参与正在进行的理论研究项目。该计划向学生介绍软材料建模的方法和挑战以及该领域研究的兴奋点。非技术摘要该职业奖支持理论和计算研究，以及由尺寸为纳米级的大分子组成的细丝组件的教育？十亿分之一米。像这样的丝状组件存在于生物细胞内，在赋予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件如何将自身组织成更复杂的结构。这对于丝状组件的结构和机械性能具有重要影响。该研究的各个方面将与使用 X 射线研究细胞中细丝成束的实验工作合作完成。该 PI 旨在揭示也适用于纳米级结构的新型合成材料设计的基本原理。这项研究是数学和物理科学与生物学边界基础研究的一个例子，有潜力推动两者的发展。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，为本科生创建软物质理论研究暑期项目。该计划旨在提高学生的技能，并使他们能够参与正在进行的理论研究项目。该课程向学生介绍软材料建模的方法和挑战以及该领域研究的兴奋点。