Lazarova T, Padrós E
Departament de Bioquímica i de Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, Spain.
Biochemistry. 1996 Jun 25;35(25):8354-8. doi: 10.1021/bi9601161.
Fourier transform infrared deconvoluted spectra of bacteriorhodopsin and the N intermediate were compared with the N/BR infrared difference spectrum. In the amide I, clear changes in the bands at 1666 cm-1, assigned to alpha II helices, 1659 cm-1, assigned to alpha I and alpha II helices, and 1652 cm-1, assigned to both alpha I helices and unordered structures, were found. These changes could arise from conversion of some alpha II and alpha I helices. Variations in the bands at 1692 and 1683 cm-1, corresponding to reverse turns, were also detected. The side chains of Tyr (band at 1517 cm-1) and Phe (band at 1498 cm-1) were found to change in going from BR to N. In the carboxylate region, no band was detected at 1737 cm-1 in the deconvoluted spectra that could correspond to the peak observed in the difference spectrum. It is argued that resolution-enhancement methods used along with difference spectra provide more detailed insights into the conformational changes occurring between photocycle intermediates.
将细菌视紫红质和N中间体的傅里叶变换红外去卷积光谱与N/BR红外差谱进行了比较。在酰胺I中，发现1666 cm-1处归属于αII螺旋的谱带、1659 cm-1处归属于αI和αII螺旋的谱带以及1652 cm-1处归属于αI螺旋和无序结构的谱带发生了明显变化。这些变化可能源于一些αII和αI螺旋的转变。还检测到了1692和1683 cm-1处对应于反向转角的谱带变化。发现从BR转变为N时，酪氨酸（1517 cm-1处的谱带）和苯丙氨酸（1498 cm-1处的谱带）的侧链发生了变化。在羧酸盐区域，去卷积光谱中未检测到1737 cm-1处可能对应于差谱中观察到的峰的谱带。有人认为，与差谱一起使用的分辨率增强方法能更详细地洞察光循环中间体之间发生的构象变化。
