Amplification of chiral recognition and discrimination among amino-acid-based nanoscale ions during assembly induced by electrostatic interaction

静电相互作用诱导组装过程中氨基酸纳米级离子之间手性识别和辨别的放大

• 批准号: 2309886
• 负责人: Tianbo Liu
• 金额: $ 39.96万
• 依托单位: University of Akron
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2026-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309886&HistoricalAwards=false
• 关键词: Amplification; chiral; recognition; discrimination; among

This award supports experimental research and education aimed at understanding how chirality is maintained and amplified during the formation of superstructures by charged macromolecules. Most biomacromolecules like proteins and DNA are chiral, that is, the same molecule has two different geometrical forms which cannot be superimposed onto its mirror image. Although both forms are considered identical in chemical and physical properties except their handedness, exclusively L-amino acids in proteins and D-sugars are found in biological systems – a phenomenon called homochirality. Many interesting phenomena have been discovered, such as that charged chiral species only seek their own kind when forming large structures (chiral recognition), and under certain conditions only one form will assemble while the other one stays as molecules in solution (chiral discrimination, which leads to homochirality). These are important topics in many fields from life sciences to catalysis and separation science. The PI will explore the conditions needed for achieving such phenomena in solution by studying nanoscale intermolecular physical interactions, especially the long-range electrostatic interaction between different chral components, which is the probable driving force. The project engages graduate and undergraduate students through the NSF-REU center, and the newly established BS program in Polymers, both at the School of Polymer Science and Polymer Eng. at the University of Akron, and high school students from northeast Ohio. The PI’s team will specifically recruit from local schools that serve large numbers of students from groups traditionally under-represented in STEM fields, encouraging students to take science courses and pursue STEM related careers.PI Tianbo Liu from the University of Akron will explore the nanoscale intermolecular interactions in dilute macroionic solutions containing multiple chiral components, by using metal-organic cages containing different chiral amino acid linkers as models . Such interactions are responsible for achieving chiral recognition (e.g., forming enantiomeric, chiral supramolecular structures instead of racemic mixed ones) and chiral discrimination and selection (e.g., only one enantiomer of chiral macroions will assemble, in the presence of small amount of chiral counterions or co-ions). The PI plans to design experiments to explore the probable key role of the long-range electrostatic interaction, represented by the interactions of chiral counterions or co-ions with the central chiral macroions, behind such phenomena, by examining the following hypotheses: (1) long-range electrostatic intermolecular interaction is critical for achieving chiral recognition between chiral macroions, resulting in pure enantiomeric supramolecular structures in racemic solutions instead of forming mixed assemblies; (2) a minor chiral environment (e.g., low concentrations of minor chiral counterions) is sufficient to achieve chiral selection (i.e., promoting one type of enantiomer to self-assemble while suppressing the other type) in chiral macroionic solution; (3) chiral selection of the metal organic cage macroions might become much more significant when the counterions (amino acids, e.g., Alanine) and the ligands of the metal organic cages are of the same type (e.g., Alanine); (4) chiral co-ions (ions carrying the same charge as the macroions) themselves alone might also be able to achieve chiral recognition and chiral selection of chiral macroions; and (5) minor chiral components can lead to the formation of chiral gels with tunable chirality. The PI’s team expects to contribute to our fundamental understanding of nanoscale intermolecular interactions by identifying the critical force leading to the chiral recognition and chiral selection of biomacromolecules, which further lead to many critical phenomena such as the homochirality feature of lives. The project engages graduate and undergraduate students through the NSF-REU center, and the newly established BS program in Polymers, both at the School of Polymer Science and Polymer Eng. at the University of Akron, and high school students from northeast Ohio. The PI’s team will specifically recruit from local schools that serve large numbers of students from groups traditionally under-represented in STEM fields, encouraging students to take science courses and pursue STEM related careers.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.

该奖项支持旨在了解带电大分子形成上层结构过程中如何保持和放大手性的实验研究和教育，大多数生物大分子（如蛋白质和DNA）都是手性的，也就是说，同一分子具有两种不同的几何形式，不能叠加。尽管两种形式除了旋向性之外在化学和物理性质上被认为是相同的，但在生物系统中只发现了蛋白质和 D-糖中的 L-氨基酸——这种现象被称为同手性。已经发现了一些现象，例如带电手性物质在形成大型结构时只寻找自己的种类（手性识别），并且在某些条件下只有一种形式会组装，而另一种形式则作为分子留在溶液中（手性歧视，这导致这些是从生命科学到催化和分离科学的许多领域的重要课题，PI将通过研究纳米级分子间物理相互作用，特别是不同手性之间的长程静电相互作用，探索在溶液中实现此类现象所需的条件。该项目通过 NSF-REU 中心以及阿克伦大学高分子科学学院和高分子工程学院新设立的高分子学士课程吸引了研究生和本科生。 PI 团队将专门从当地学校招募来自 STEM 领域传统上代表性不足的群体的高中生，鼓励学生学习科学课程并从事 STEM 相关职业。PI Tianbo Liu，来自该大学阿克伦的研究人员将通过使用含有不同手性氨基酸连接体的金属有机笼作为模型，探索含有多种手性组分的稀大分子离子溶液中的纳米级分子间相互作用。这种相互作用负责实现手性识别（例如，形成对映体、手性超分子结构）。的种族混合）和手性歧视和选择（例如，在存在少量手性大分子的情况下，只有一种手性大分子对映体会聚集） PI 计划设计实验，通过检查这些现象背后的长程静电相互作用（以手性反离子或共离子与中心手性大离子的相互作用为代表）可能的关键作用。以下假设：（1）长程静电分子间相互作用对于实现手性大分子之间的手性识别至关重要，从而在种族溶液中产生纯对映体超分子结构而不是形成混合组装体； (3) 当金属有机笼的抗衡离子（氨基酸，例如丙氨酸）和金属有机笼的配体属于同一类型时（例如， （4）手性共离子（与大离子带有相同电荷的离子）本身也可能能够实现手性大离子的手性识别和手性选择；（5）次要手性组分可以导致形成具有可调性的手性凝胶。 PI 的团队希望通过确定导致生物大分子手性识别和手性选择的关键力，从而进一步促进我们对纳米级分子间相互作用的基本理解。该项目通过 NSF-REU 中心以及阿克伦大学高分子科学学院和高分子工程学院新设立的高分子学士项目吸引了研究生和本科生。以及来自俄亥俄州东北部的高中生。PI 团队将专门从当地学校招募学生，这些学校为传统上在 STEM 领域代表性不足的群体提供服务，鼓励学生学习科学课程并从事 STEM 相关职业。通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。