RII Track-4: Using STM to Examine the Origin of Biological Homochirality in Amino Acids from Ultra-High Vacuum to Liquid Environments

这个项目的重点是阐明氨基酸表面的基础科学，通过比较在仔细控制的条件下的特征与那些更接近现实世界的条件。与NSF的使命一致，该项目将使人们更深入地了解小的益生元分子如何与表面相互作用，并参与生物学上适用的前体的出现。在基础层面上，该项目将研究氨基酸分子如何相互作用，以及这些相互作用如何与蛋白质等生物相关结构相关联。重要的是，在高端显微镜（低温，高真空）上进行的单分子研究与在不太理想的显微镜（室温，典型大气压）上进行的研究相结合，对于研究生物学相关系统既新颖又必不可少。虽然单分子研究通常在原始条件下进行，但很少将这些研究与现实世界中的相同系统结合起来。研究成果将对我们了解金属表面的益生元分子及其演化具有重要意义。这项研究的发现将用于教育活动，以展示如何利用基础科学对氨基酸和这个星球上生物活性分子的起源做出更广泛的预测。长期以来，科学家对生物分子的特定手性的偏好一直很感兴趣。手性对称是如何被打破并最终偏向于左旋分子的，这个问题对于理解地球上生命的起源至关重要。作为理解这些过程的一步，单个分子在表面上的组装可以用现代表面科学技术来研究。低温，超高真空，扫描隧道显微镜（LT-UHV STM）将用于捕获精确的分子排列，然后将与液体和电化学STM （EC-STM）相结合，以复制模型系统的生物条件，如金属上的氨基酸。除了以纳米级分辨率成像分子自组装外，STM图像还将用于了解手性传播和识别，这直接适用于生命起源的研究。除了手性转移之外，这些生物系统还与研究不同氨基酸残基对二级结构的偏好有关。为了研究这些系统，提出了几个研究目标：(1)建立分子组装的基线，以及分子吸附如何改变特高压下的金属底物。(2)使用环境、液体和EC-STM来确定观察到的特高压行为是否可以扩展到更现实的条件。(3)研究l -氨基酸的手性如何在特高压下通过二维表面传递。该建议解决了确定模型手性表面研究与在相关生化条件下以类似分辨率进行的研究之间的联系的关键需求。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Description This project focuses on elucidating fundamental science on the surfaces of amino acids by comparing characterizations under carefully controlled conditions with those closer to real-world conditions. In line with NSF's mission, this project will lead to a deeper understanding of how small, prebiotic molecules interact with surfaces and participate in the emergence of biologically applicable precursors. On a fundamental level, this project will study how amino acid molecules interact and how those interactions correlate to biologically relevant structures like proteins. Importantly, the association of single-molecule studies performed on a high-end microscope (low temperature, high vacuum) with studies performed on a less-ideal microscope (room temperature, typical atmospheric pressure) is both novel and essential to studying biologically relevant systems. While single molecule studies are often performed in pristine conditions, it is rare that those studies are combined with the same systems in the real-world. Research outcomes will make significant contributions to our understanding of prebiotic molecules and the evolution of those molecules on metallic surfaces. The findings of this research will be used at educational events to demonstrate how fundamental science can be used to make broader predictions about amino acids and the beginning of biologically-active molecules on this planet. Technical Description The preference for a specific handedness of biological molecules has long intrigued scientists. The question of how chiral symmetry was broken and subsequently biased towards left-handed molecules is central to the understanding of the origin of life on this planet. As a step towards understanding such processes, the assembly of individual molecules on surfaces can be studied with modern surface science techniques. Low-temperature, ultra-high vacuum, scanning tunneling microscopy (LT-UHV STM) will be used to capture exact molecular arrangements, which will then be coupled with liquid and electrochemical STM (EC-STM) to replicate biological conditions for model systems such as amino acids on metals. In addition to imaging molecular self-assembly with nanoscale resolution, STM images will be used to understand chiral propagation and recognition, which is directly applicable to origin of life studies. Beyond the transfer of chirality, these biological systems are relevant for the study of the preference for secondary structures by different amino acid residues. In order to study these systems, several research objectives are proposed: (1) Establish a baseline for molecular assembly and how molecular adsorption alters the underlying metal substrate in UHV. (2) Use ambient, liquid, and EC-STM to determine if the observed UHV behavior can be extended to more realistic conditions. (3) Investigate how the chirality of L-amino acids is transmitted across a 2D surface in UHV. This proposal addresses the critical need to ascertain a connection between model chiral surface studies and studies performed with similar resolution under relevant biochemical conditions.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.