Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA.
Photochem Photobiol. 2010 Mar-Apr;86(2):316-23. doi: 10.1111/j.1751-1097.2009.00666.x. Epub 2009 Dec 7.
The spectroscopic and kinetic studies of the interaction between bacteriorhodopsin in the M-intermediate and several surfactants (cetyl trimethyl ammonium bromide, dodecyl trimethyl ammonium bromide, diethylene glycol mono-n-hexyl ether, ethylene glycol mono-n-hexyl ether, sodium 1-decanesulfonate and sodium 1-heptanesulfonate) have been investigated using steady-state UV-VIS spectrometry and time-resolved absorption techniques. The steady-state spectral results show that bR retains its trimeric state. Time-resolved observations indicate that the rate of deprotonation of the protonated Schiff base increases in the presence of the cationic surfactants, whereas insignificant changes are observed in the neutral or anionic surfactants. The rate of the reprotonation of the Schiff base in the transition M --> N is accelerated in anionic and neutral surfactants, but is decelerated in the presence of the cationic surfactants. Surfactants with a longer hydrocarbon tail have a greater effect on the kinetics when compared with surfactants having shorter hydrocarbon tails. The opposite effect is observed when the hydrophilic head of the surfactants contains opposite charges. These distinct kinetics are discussed in terms of the difference in the modified surface hydrophilicity of the bR and the possible protein configurational changes upon surfactant treatments.
用稳态紫外可见光谱法和时间分辨吸收技术研究了菌紫质（M 中间态）与几种表面活性剂（十六烷基三甲基溴化铵、十二烷基三甲基溴化铵、二甘醇单正己基醚、乙二醇单正己基醚、十烷磺酸钠和庚烷磺酸钠）相互作用的光谱和动力学。稳态光谱结果表明 bR 保持三聚体状态。时间分辨观察表明，在阳离子表面活性剂存在下，质子化席夫碱的去质子化速率增加，而在中性或阴离子表面活性剂中观察到的变化不明显。在 M-N 跃迁中，席夫碱的再质子化速率在阴离子和中性表面活性剂中加速，但在阳离子表面活性剂中则减速。与具有较短烃尾的表面活性剂相比，烃尾较长的表面活性剂对动力学的影响更大。当表面活性剂的亲水头带有相反电荷时，会观察到相反的效果。这些不同的动力学可以根据 bR 的表面亲水性的差异以及表面活性剂处理后可能发生的蛋白质构象变化来讨论。
