VIBRATIONAL OPTICAL ACTIVITY IN BIOLOGICAL MOLECULES

振动光学活性(VOA)，它由拉曼光学组成 活度(ROA)和振动圆二向色性(VCD)，将 在工具、解释和理论方面取得进展 改进现有测定方法的目的是 生物分子的溶液相构象。多通道ROA 光谱仪将通过更换OMA 2计算机控制台进行升级 具有OMA III控制台，并添加了多通道功能 电荷耦合器件(CCD)探测器实现更大的仪器化 可靠性和光谱灵敏度。新的工具性方法 我们最近构思和设计的ROA量度 实验室，称为散射圆偏振(SCP)ROA 和双圆偏振(DCP)ROA，将用于其 与传统的ROA测量相比，提高了效率和稳定性 技术，称为入射圆极化(ICP)ROA。 测量最初将集中在已经有 在溶液中表现出很强的ROA光谱，并将朝着类似的方向发展 更复杂的分子。测量的方法和方法 还将探讨共振ROA。这样的测量是有意义的 因为它们的结构选择性和理论上的 SCP和ICPROA之间的差异预计将在以下情况下加强 共振拉曼条件。美国之音在研究中的应用 VCD的测量将突出生物分子的构象 使用锡拉丘兹现有的三台VCD光谱仪中的任何一台 大学。要测量的样品包括氨基酸，简单 多肽、甘油醛、儿茶酚胺类神经递质分子， 三脚架肽、叠氮高铁血红蛋白和叠氮肌红蛋白，以及 其他精选蛋白质、胺、醇、糖和相关物质 分子。VCD光谱将通过使用或扩展来解释 环电流强度机制的规则或通过应用 耦合振子强度机制。我们将特别注意 致力于VCD的灵敏度，通过环电流机制， 分子内氢键的存在，其中一些涉及 只有分子内缔合的弱形式，如氧孤对 到脂肪族碳氢相互作用。振动耦合 VCD和ROA强度的表达及其与实验的比较 结果。重点将放在以下方面的结果： 对基本的美国之音模型和解释方法的计算， 如VCD的环流机制。模型二醇和氨基 醇、丙氨酸和氚甘氨酸将成为最初的目标 用于计算。与前几年一样，这一行动的主要重点是 研究将集中在氨基酸和多肽分子上；然而，研究 在其他类型的分子上，这些分子非常适合这个目标 该计划将作为美国之音更灵活方法的一部分 研究。

Vibrational optical activity (VOA), which is comprised of Raman optical activity (ROA) and vibrational circular dichroism (VCD), will be advanced along instrumental, interpretational and theoretical lines with the aim of improving existing methods for the determination of the solution-phase conformations of biomolecules. A multichannel ROA spectrometer will be upgraded by replacing the OMA 2 computer console with an OMA III console and adding the capability of a multichannel charge coupled device (CCD) detector to achieve greater instrumental reliability and spectral sensitivity. New instrumental approaches to the measurement of ROA, recently conceived and devised in our laboratory, and referred to as scattered circular polarization (SCP) ROA and dual circular polarization (DCP) ROA, will be exploited for their enhanced efficiency and stability over conventional ROA measurement techniques, termed incident circular polarization (ICP) ROA. Measurements will focus initially on molecules that have already exhibited strong ROA spectra in solution and will proceed toward similar molecules of greater complexity. Approaches to the measurement of resonance ROA will also be explored. Such measurements are of interest because of their structural selectivity and because theoretical differences between SCP and ICP ROA are predicted to be enhanced under resonance Raman conditions. Applications of VOA to the study of biomolecular conformations will be highlighted by measurements of VCD using any one of three existing VCD spectrometers at Syracuse University. Samples to be measured include amino acids, simple peptides, glyceraldehyde, catecholamine neurotransmitter molecules, tripodal peptides, azidomethemoglobin and azidometmyoglobin, and additional selected proteins, amines, alcohols, sugars and related molecules. The VCD spectra will be interpreted by using or extending the rules of the ring current intensity mechanism or by applying the coupled oscillator intensity mechanism. Particular attention will be devoted to the sensitivity of VCD, via the ring current mechanism, to the presence of intramolecular hydrogen bonds, some of which involve only weak forms of intramolecular association such as oxygen lone pair to aliphatic carbon hydrogen interactions. Vibronic coupling expressions of VCD and ROA intensities and comparison to experimental results. Emphasis will be placed on relating the results of calculations to elementary VOA models and interpretational approaches, such as the ring current mechanism of VCD. Model diols and amino alcohols, alanine and deuteriated glycine will serve as initial targets for calculations. As in previous years, the primary focus of this research will be on amino acids and peptide molecules; however, research on other types of molecules that are well suited to the goals of this program will be pursued as part of a more flexible approach to VOA research.