NSF/MCB BSF: Direct Force measurements and analysis of intrinsically disordered proteins

NSF/MCB BSF：本质无序蛋白质的直接力测量和分析

• 批准号: 1715627
• 负责人: Omar Saleh
• 金额: $ 76.42万
• 依托单位: University of California-Santa Barbara
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1715627&HistoricalAwards=false
• 关键词: NSF; MCB; BSF; Direct; Force

Many important structures within organisms are built out of proteins, large string-shaped molecules that typically coil up ('fold') into a well-defined globular shape. However, recent discoveries have found that there is a rather large subset of proteins (including about 30% of the proteins in humans) that do not fold; instead, their shape continually fluctuates like a wriggling piece of spaghetti. These disordered proteins are also distinguished from folded proteins by their composition and typically contain a larger number of electrically-charged subunits in comparison to folded proteins. This project will investigate the link between the highly-charged composition and the fluctuating structure of disordered proteins. The experiments conducted using modern physical methods that will permit new insight into protein shape and its fluctuations. This project will particularly focus on important proteins found in muscle and in neurons. This research project will have broad, long-term impacts in training young scientists, as well as forming an international collaboration. Intrinsically-disordered proteins (IDPs) are frequently enriched in charged residues, and subject to regulatory control through phosphorylation. Thus, electrostatic interactions are dominant in defining and modulating chain structure. For IDPs, structure is a dynamic concept, as the proteins fluctuate through a large ensemble of available conformationa. The overarching goal of this proposal is to study the effects of electrostatic interactions on dynamic IDP structure. This project will focus on two important disordered proteins: i) the PEVK region of the muscle protein titin, a highly-charged domain whose entropic elasticity helps define the passive elasticity of muscle; and ii) the C-terminal tails of neuromuscular intermediate filament (NIF) proteins, whose electrostatic interactions drive the assembly of filaments into hydrogel networks that define the cytoskeleton of axons. The dynamic structure of PEVK and NIFs will be studied by using quantitative experimental methods and concepts derived from soft-matter physics, including low-force single-molecule stretching to infer dynamic structure from entropic elasticity, and small-angle X-ray scattering (SAXS) measurements. Electrostatic effects will be studied by exploring the effect on structure of different solution salt conditions, as well as exploring the effects of phosphorylation, and of varying chain charge profiles. The combination of SAXS and single-molecule manipulation measurements will lead to quantitative, microscopic insight into biologically-relevant mechanisms of electrostatic control of IDP structure. This collaborative US/Israel project is supported by the US National Science Foundation and the Israeli Binational Science Foundation.

生物体内的许多重要结构都是由蛋白质组成的，蛋白质是一种大的线状分子，通常卷曲(折叠)成明确的球状形状。然而，最近的发现发现，有相当大一部分蛋白质(包括人类约30%的蛋白质)不会折叠；相反，它们的形状不断波动，就像一块蠕动的意大利面。这些无序蛋白质的组成也与折叠蛋白质不同，与折叠蛋白质相比，这些无序蛋白质通常含有更多的带电亚基。这个项目将研究无序蛋白质的高电荷态组成和波动结构之间的联系。使用现代物理方法进行的实验将允许对蛋白质形状及其波动的新见解。该项目将特别关注在肌肉和神经元中发现的重要蛋白质。这一研究项目将在培养年轻科学家以及形成国际合作方面产生广泛和长期的影响。固有无序蛋白(IDPs)经常富含带电残基，并通过磷酸化受到调控。因此，静电相互作用在定义和调节链结构中占主导地位。对于IDPs来说，结构是一个动态的概念，因为蛋白质在一大堆可用构象a中波动。该方案的主要目标是研究静电相互作用对动态IDP结构的影响。这个项目将集中在两个重要的无序蛋白质：i)肌肉蛋白titin的PEVK区域，一个高电荷域，其熵弹性有助于定义肌肉的被动弹性；ii)神经肌肉中间丝(NIF)蛋白质的C末端尾部，其静电相互作用驱动细丝组装成水凝胶网络，定义轴突的细胞骨架。PEVK和NIF的动态结构将通过使用来自软物质物理的定量实验方法和概念来研究，包括从熵弹性推断动态结构的低力单分子拉伸，以及小角X射线散射(SAXS)测量。静电效应将通过探索不同的溶液盐条件对结构的影响，以及探索磷酸化和不同的链电荷分布的影响来研究。SAXS和单分子操纵测量的结合将导致对IdP结构的静电控制的生物相关机制的定量、微观的洞察。这一美国和以色列的合作项目得到了美国国家科学基金会和以色列双国科学基金会的支持。

项目成果

Glassy Dynamics and Memory Effects in an Intrinsically Disordered Protein Construct

本质上无序的蛋白质结构中的玻璃动力学和记忆效应

• DOI: 10.1103/physrevlett.125.058001
• 发表时间: 2020
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Morgan, Ian L.;Avinery, Ram;Rahamim, Gil;Beck, Roy;Saleh, Omar A.
• 通讯作者: Saleh, Omar A.

Intrinsically disordered proteins at the nano-scale

• DOI: 10.1088/2399-1984/abfb7c
• 发表时间: 2021-06-01
• 期刊: NANO FUTURES
• 影响因子: 2.1
• 作者: Ehm, T.;Shinar, H.;Beck, R.
• 通讯作者: Beck, R.

Surface-induced effects in fluctuation-based measurements of single-polymer elasticity: A direct probe of the radius of gyration

• DOI: 10.1063/1.5009049
• 发表时间: 2018-03-28
• 期刊: JOURNAL OF CHEMICAL PHYSICS
• 影响因子: 4.4
• 作者: Innes-Gold, Sarah N.;Morgan, Ian L.;Saleh, Omar A.
• 通讯作者: Saleh, Omar A.