Tuma R, Vohník S, Li H, Thomas G J
Division of Cell Biology and Biophysics, School of Biological Sciences, University of Missouri-Kansas City 64110.
Biophys J. 1993 Sep;65(3):1066-72. doi: 10.1016/S0006-3495(93)81172-X.
The bond stretching vibration of the cysteine sulfhydryl (SH) group in a typical protein generates a Raman band in the spectral interval 2500-2600 cm-1, a region devoid of interference from any other fundamental mode of vibration of the protein. The relatively high Raman cross section associated with the S-H stretching vibration, the sensitivity of the vibrational frequency to hydrogen bonding interactions and side chain configurations, and the dependence of the Raman intensity on thiol-thiolate equilibria, combine to make the Raman SH band a potentially valuable marker of protein sulfhydryl interactions and a unique indicator of sulfhydryl participation in thiol-disulfide oxidoreductase activity. In order to exploit Raman spectroscopy for these purposes, accurate and precise measurements of Raman SH band profiles are required. We show here that the required precision and accuracy can be achieved by use of the Raman band corresponding to the stretching vibration of in situ nitrogen gas as a quantitative intensity and frequency standard. The Raman Q-branch center of the N2 band occurs at 2330.7 cm-1.
典型蛋白质中半胱氨酸巯基（SH）基团的键伸缩振动在2500 - 2600 cm-1光谱区间产生拉曼带，该区域没有蛋白质任何其他基本振动模式的干扰。与S - H伸缩振动相关的相对较高的拉曼截面、振动频率对氢键相互作用和侧链构型的敏感性以及拉曼强度对硫醇 - 硫醇盐平衡的依赖性，共同使得拉曼SH带成为蛋白质巯基相互作用的潜在有价值标记以及巯基参与硫醇 - 二硫键氧化还原酶活性的独特指标。为了将拉曼光谱用于这些目的，需要对拉曼SH带轮廓进行准确和精确的测量。我们在此表明，通过使用对应于原位氮气伸缩振动的拉曼带作为定量强度和频率标准，可以实现所需的精度和准确性。N2带的拉曼Q支中心出现在2330.7 cm-1处。
