不同pH条件下细菌视紫红质的共振拉曼光谱研究

本实验测定了不同pH条件下嗜盐菌紫膜中细菌视紫红质(bR)的共振拉曼光谱.13-顺式视黄醛生色团的特征峰1187cm~(-1)和全反式、13-顺式共有的特征峰1200cm~(-1)带强度之比I_(1187)/I_(1200)在pH1.0-8.9之间约为0.76,而pH高于8.9为0.97.pH3.0-9.0时C=NH~ 振动峰为1640-1642cm~(-1),pH9.4以上为1642-1644cm~(-1),pH9.2附近变化最大,pH3.0以下低于1640cm~(-1).酸性和弱碱性范围时,19-CH_3和20-CH_3的面内变形振动与面外变形振动相互重叠,碱性范围分为双峰.并讨论了对结构及其稳定性的影响.

RESONANCE RAMAN STUDY OF BACTERIO-RHODOPSIN AT DIFFERENT pH

Resonance Raman spectra of Bacteriorhodopsin(bR) were obtained at different pH. I1187/I1200 which is intensity ratio of both characteristic vibration band of 13-cis retinyl chromophore 1187cm-1 and common one of 13-cis and all-trans retinyl chromophore 1200cm-1 is about 0.75 at pH 1.0-8.9, 0.97 above 8.9. The C= NH+ vibration frequencies appear at 164G-1642cm-1 between pH 3.0 and 9.0, 1642-1644cm-1 above pH 9.4. The transition is near pH 9.2. The vibration frequencies are lower than 1640cm-1 in the range of pH 1.0-3.0. The in-plane and out-plane deformation vibrations of the 19-CH3 and 20-CH3 overlaps with each other in the acid and weak alkaline range, becomes two peaks in the alkaline range. The influence of pH on the structre and stability of bR has been discussed.