Wolpert Martina, Hellwig Petra
Institut für Biophysik, Johann Wolfgang Goethe-Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt/Main, Germany.
Spectrochim Acta A Mol Biomol Spectrosc. 2006 Jul;64(4):987-1001. doi: 10.1016/j.saa.2005.08.025. Epub 2006 Feb 7.
In this work, we present the absorption spectra and molar coefficients of all 20 amino acids in aqueous solutions down to 500 cm(-1). The spectral region between 1200 and 500 cm(-1) was yet disregarded for protein infrared spectroscopy, mainly due to the strong H(2)O absorption. Absorption spectra were obtained mainly for physiological relevant pH region. Intense bands for aromatic amino acids, histidine and such with OH group could clearly be identified throughout the given spectral region. For sulfur-containing amino acids cysteine and methionine some strong bands besides the weak carbon-sulfur stretching vibration was shown. Effects of aqueous solution environment, pH, protonation states were discussed, together with previously reported data from theoretical approaches. With this complete set of spectral information application to proteins in the whole mid infrared region could be described precise and the potential of the lower spectral region to study typical cofactor ligands like histidine, shown.
在本工作中，我们给出了所有20种氨基酸在水溶液中低至500 cm⁻¹的吸收光谱和摩尔系数。1200至500 cm⁻¹的光谱区域在蛋白质红外光谱中一直被忽视，主要是由于水的强烈吸收。吸收光谱主要是在生理相关的pH区域获得的。在给定的光谱区域内，可以清楚地识别出芳香族氨基酸、组氨酸以及含羟基氨基酸的强吸收带。对于含硫氨基酸半胱氨酸和甲硫氨酸，除了弱的碳 - 硫伸缩振动外，还显示出一些强吸收带。讨论了水溶液环境、pH值、质子化状态的影响，并与先前理论方法报道的数据进行了比较。有了这一整套光谱信息，就可以精确描述在整个中红外区域对蛋白质的应用，并且展示了较低光谱区域研究典型辅因子配体（如组氨酸）的潜力。
