尿嘧啶的相干反斯托克斯Raman散射光谱研究

Study on Coherent Anti- Stokes Raman Spectra of Uracil

采用相干反斯托克斯Raman散射(CARS)技术研究在不同pH值的水溶液中核糖核酸碱基-尿嘧啶结构,所得结果揭示出尿嘧啶环的伸缩,变形振动可在1000cm^(-1)附近产生一些Raman谱线,并发现这些谱线对溶液的pH值很敏感。然而这些现象在采用目前广泛应用的激光共振Raman光谱方法时是难以发现的。因此,CARS测量是一种可研究核酸残基振动结构及其和环境介质相互作用的有效方法。除它对样品或杂质引起的荧光干扰有明显抑制作用外,可以预期:这一方法也可用于获得在有关分子过程中所出现的瞬态粒子结构的信息。

Current interest in the molecular mechanism of gene engineering places great importance on the structural probing of nucleic acids . In this paper preliminary study on the structure of uracil , a base residue of RNA , in aqueous solu -tions of different pH values by coherent anti - Stokes Raman scattering (CARS) is reported .The results obtained reveal Raman lines associated with the stretching and bending vibration modes of the uracil ring around 1 000 cm-1. It is also found that these Raman lines are sensitive to pH of the solutions used . All these findings , however , are difficult to be observed by laser resonance Raman spectrosccpy which is used widely in practice at present .Therefore , we conclude that CARS measurement seems to be a powerful tool capable of offering structural specificity associated with molecular vibrational frequencies of base residues of nucleic acids and their interaction with the surrounding media . In addition to a significant suppression of interference from fluorescence either intrinsic to the sample or caused by impurities , this approach is expected to be able to provide structural information of transient species during relavant molecular processes .