Infrared spectroscopic studies of ionic and neutral biomolecules and their solvated complexes

建议的研究重点是中性和离子分子和络合物的结构阐明，特别是那些能够参与弱分子内键合的分子和络合物。蛋白质和其他生物分子在其自然状态下是多重质子化的。它们还可以与金属阳离子结合，这通常是生物活性所必需的。这项拟议的研究将通过研究分离于稀有气体基质中的这些物种在低温下的红外光谱，提供对存在于生物相关分子中的显著的弱分子内相互作用的洞察，这些物种可以在那里无限期地储存和研究。例如，当甘氨酸与钠离子结合时，可以通过红外吸收位置的变化来研究与分子另一部分的相互作用(分子内结合)的程度。例如，当甘氨酸与钠离子结合时，其中一种异构体有望在羰基氧和氨基氢之间表现出强烈的分子内氢键。由于N-H拉伸比正常的N-H拉伸红移了约800个波数。我们将研究顺序溶剂化(用1、2或更多的溶剂分子，如水)生物上感兴趣的离子和中性的影响，以便弥合气相分子的固有性质与其自然溶剂化状态的分子的内在性质之间的差距。有了拟议的实验，我们将能够评估在每个阶段溶剂化过程中发生的结构变化。这项研究有望在确定生命构件的结构以及溶剂对结构的影响方面发挥重要作用。这将导致对生物分子的作用和溶剂在生物活性中的作用有更详细、更基本的了解。此外，这项研究将提供生物离子和中性物质的光谱特征，最终有助于使用红外光谱进行诊断。

The proposed research is focused on the structure elucidation of both neutral and ionic molecules and complexes, especially those which can participate in weak intramolecular bonding.  In their natural state, proteins and other biological molecules are multiply protonated. They can also be bound to metal cations and this is often required for biological activity.  The proposed research will provide insight into the salient weak intramolecular interactions which are present in biologically relevant molecules by studying the infrared spectra of these species isolated in rare-gas matrices at cryogenic temperatures where they can be stored and studied indefinately.  The degree of interaction with another portion of the molecule (intramolecular bonding) can be studied by the shifts in  position of the infrared absorption.  For example, when glycine is bound to a sodium cation, one of the isomers is expected to exhibit strong intramolecular hydrogen bonding between a carbonyl oxygen and an amino hydrogen.  The N-H stretch is seen to red-shift by some 800 wavenumbers from that of a normal N-H stretch.   The effect of sequentially solvating (with 1, 2 or more solvent molecules such as water) biologically interesting ions and neutrals will be studied in order to bridge the gap between the intrinsic properties of the gas-phase molecule and those of the molecule in its natural, solvated state.  With the proposed experiments we will be able to assess the structural changes which occur at each stage solvation. This research is expected to play an important role in determining the structure, and the effect of solvent on the structure, of life's building blocks.  This will lead to a more detailed, fundamental understanding of the role of the biomolecule and the role of solvent in biological activity.  Furthermore, this research will provide spectral signatures for biological ions and neutrals which can eventually aid in the use of infrared spectroscopy for diagnostic purposes.