Photochemistry of two rhodopsinlike pigments in bacteriorhodopsin-free mutant of Halobacterium halobium.
Photochemistry of two rhodopsinlike pigments in bacteriorhodopsin-free mutant of Halobacterium halobium.
复制标题
盐杆菌无细菌视紫红质突变体中两种视紫红质样色素的光化学。
DOI：
10.1016/s0006-3495(83)84277-5
复制
发表时间：
1983
影响因子：
3.4
通讯作者：
M. Tsuda
中科院分区：
文献类型：
--
作者：
N. Hazemoto;N. Kamo;Y. Terayama;Y. Kobatake;M. Tsuda
在盐杆菌的无细菌视紫红质突变体的膜囊泡中发现了由两种不同色素引起的两个光循环。吸收大约 590 nm 的盐视紫红质 (HR) 的颜料经历了更快的光循环，在大约 490 nm 处有光瞬变（半衰期，tau 1/2 = 10 ms）。另一种吸收约 580 nm 波长的第三类视紫红质色素 (TR) 经历了较慢的光循环，并伴随着低于 410 nm 的光瞬态吸收（tau 1/2 = 0.8s）。在不同的温度、氯化钠浓度、pH 值和胆酸盐存在的条件下测量光循环。获得的所有结果都支持两个光循环彼此独立的观点，并且在这些处理后可以废除快循环或慢循环。在碱性 pH 值下，两种颜料的最大吸光度波长均移至蓝色，但经历缓慢光循环的颜料的位移幅度比另一种颜料大得多。两种色素的含量比例在无细菌视紫红质突变体中有所不同。
Two photocycles due to two different pigments were found in membrane vesicles of a bacteriorhodopsin-free mutant of Halobacterium halobium. A pigment absorbing approximately 590 nm halorhodopsin (HR) underwent a faster photocycle with a phototransient at approximately 490 nm (half-time of decay, tau 1/2 = 10 ms). Another third rhodopsinlike pigment (TR) absorbing approximately 580 nm underwent a slower photocycle accompanying a phototransient absorbing below 410 nm (tau 1/2 = 0.8s). The photocycles were measured under various conditions of temperature, NaCl concentration, pH, and in the presence of cholate. All results obtained support the notion that the two photocycles are independent of each other, and the fast or the slow cycle can be abolished after these treatments. At alkaline pH, the wavelength of maximum absorbance of both pigments shifted to blue, but the magnitude of the shift of the pigment undergoing the slow photocycle was much greater than the other. The ratio of the content of the two pigments varies among bacteriorhodopsin-free mutants.