2D IR OF GUANIDINE IN WATER

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 最近的FTIR研究表明，胍溶液中水的OH伸缩模式在胍加入后，O-H伸缩模式的频率向较低频率移动，引起了胍离子周围水分子的溶剂化壳层结构的问题。胍常用作蛋白质变性剂。它可以作为变性剂，因为它直接与蛋白质结合，因为它有3个NH 2基团，模拟水分子的氢键能力。 这个项目的目标是生成胍和水之间相互作用的微观描述，并推断为什么胍在生物学中作为变性剂如此有效。据推测，胍改变了水网络的结构。通过使用双频2D-IR，我们能够可视化胍与周围水之间的相互作用以及水-水相互作用。通过使用2D-IR，我们应该能够区分以下几点：胍周围的水分子是否与大量的水分离？溶剂化壳OH伸缩模式的频率波动是否表明与离子的耦合？或者胍周围的水分子在物理性质上与本体水相似？

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Recent FTIR investigations of the OH stretch mode of water in guanidine solutions revealed a large frequency shift to lower frequency of the O-H stretch mode after guanidine addition, arising questions about the structure of the solvation shell of water molecules around the guanidine ions. Guanidine is often used as a protein denaturant. It may act as a denaturant because it binds to proteins directly since it has 3 NH2 groups that mimic water molecules in their H-bonding ability. The goal of this project is to generate a microscopic description of the interaction between guanidine and water and deduce why guanidine is so effective as a denaturant in biology. It has been postulated that guanidine changes the structure of the water network. By using dual frequency 2D-IR, we are able to visualize the interaction between guanidine and the surrounding water as well as the water-water interactions. By using 2D-IR, we should be able to tell between the following: Are the water molecules surrounding guanidine isolated from the bulk water? Do the frequency fluctuations of the OH stretch modes of the solvation shell manifest coupling to the ion? Or are the water molecules surrounding guanidine similar in their physical properties to the bulk water?