'WET' ELECTROSTATICS AND BIOMOLECULAR SELF-ASSEMBLY

“湿”静电和生物分子自组装

• 批准号: 8362080
• 负责人: GERARD C WONG
• 金额: $ 0.74万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8362080
• 关键词: Bacteria; Behavior; Biopolymers; Capsid; Charge; Chromosomes; Complex; DNA; DNA Packaging; Electrostatics; Exhibits; F-Actin; Funding; Genetic Engineering; Grant; Histones; Intuition; Ions; Lactoferrin; Membrane; Molecular; Muramidase; National Center for Research Resources; Physical condensation; Principal Investigator; Protamines; Proteins; Radiation; Research; Research Infrastructure; Resources; Salts; Series; Solutions; Source; Techniques; United States National Institutes of Health; Viral; Work; aqueous; cost; globular protein; macromolecule; mutant; programs; retinal rods; self assembly; structural biology; theories

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. 'Wet' electrostatic interactions are poorly understood and often exhibit counterintuitive behavior. For example, two like-charged macromolecules in aqueous solution are expected to repel one another, which is essentially the prediction of prevailing mean-field theories. In the presence of multivalent ions, however, many biopolymers actually attract one another and condense into compact, ordered states. Examples include DNA condensation by charged histones in chromosomes, and DNA packaging by multivalent protamines in bacteria and viral capsids. In our previous work at SSRL, we have directly observed a molecular mechanism for attractions between rod-like polyelectrolytes by observing counterion organization. The aim of the present proposed program is to develop our intuition for more complex forms of electrostatic assembly. We will examine a series of paradigmatic examples of interactions between simple geometric objects, such as complexes formed between like-charged rods and sheets (anionic DNA and anionic membranes), or complexes formed between oppositely charged rods and spheroids (F-actin and monodisperse cationic globular proteins (lysozyme, lactoferrin)) in the presence of salts of different valence. In particular, we will take advantage of genetic engineering techniques to make mutant proteins with essentially the same size but with different net charges and charge distributions, and examine how these changes impinge on their self-assembly behavior.

该子项目是利用资源的众多研究子项目之一 由 NIH/NCRR 资助的中心拨款提供。子项目的主要支持 并且子项目的首席研究员可能是由其他来源提供的， 包括其他 NIH 来源。 子项目可能列出的总成本 代表子项目使用的中心基础设施的估计数量， NCRR 赠款不直接向子项目或子项目工作人员提供资金。 人们对“湿”静电相互作用知之甚少，并且经常表现出违反直觉的行为。例如，水溶液中两个带同电荷的大分子预计会相互排斥，这本质上是流行的平均场理论的预测。然而，在多价离子存在的情况下，许多生物聚合物实际上会相互吸引并凝结成紧凑的有序状态。例子包括染色体中带电组蛋白的 DNA 浓缩，以及细菌和病毒衣壳中多价鱼精蛋白的 DNA 包装。在SSRL之前的工作中，我们通过观察反离子组织直接观察了棒状聚电解质之间吸引力的分子机制。目前提出的计划的目的是培养我们对更复杂形式的静电组装的直觉。我们将研究一系列简单几何物体之间相互作用的范例，例如带同电荷的杆和片（阴离子 DNA 和阴离子膜）之间形成的复合物，或带相反电荷的杆和球体（F-肌动蛋白和单分散阳离子膜）之间形成的复合物。球状蛋白（溶菌酶、乳铁蛋白））在不同价态的盐存在下。特别是，我们将利用基因工程技术来制造大小基本相同但净电荷和电荷分布不同的突变蛋白，并研究这些变化如何影响它们的自组装行为。