Bioenergetic role of halorhodopsin in Halobacterium halobium cells
Bioenergetic role of halorhodopsin in Halobacterium halobium cells
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盐视紫红质在盐杆菌细胞中的生物能作用
DOI：
10.1016/0014-5793(81)80399-7
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发表时间：
1981
期刊：
影响因子：
3.5
通讯作者：
J. Lanyi
中科院分区：
文献类型：
--
作者：
G. Wagner;D. Oesterhelt;G. Krippahl;J. Lanyi
盐生盐杆菌膜中的生物能功能依赖于黑暗中的呼吸，以及照明期间的两种视网膜色素。其中最著名的是细菌视紫红质[1]，它存在于覆盖多达50%细胞表面的晶体阵列（补丁）中。细菌视紫红质是光依赖性质子泵，并且已经提出[2-4]，pH差，特别是在光照期间通过质子挤出穿过细胞质膜而产生的电势，是ATP合成的供能因子。光照确实会支持含有细菌视紫红质的H。盐细菌在严格厌氧条件下的第二种视网膜色素是盐视紫红质。这种色素是钠离子的光驱动生电泵[6-8]，其光谱特性与细菌视紫红质的光谱特性有些不同[9，10]。这种泵的存在是最容易识别的细胞包膜囊泡制备H。缺乏细菌视紫红质的盐生菌菌株。这种囊泡的照明导致解偶联剂促进的被动质子吸收，直到pH差（内部为酸）被膜电位（内部为负）平衡，因此质子动力为零[8]。从野生型含有细菌视紫红质的细胞中适当制备的囊泡在光照下显示出主动和被动质子运动[7，8]，前者表现为流出，后者表现为流入。质子导体将倾向于抑制质子流出，但增强流入。因此，当存在时，似乎两个泵都以向外的方向取向，缩写：CCCP，羰基氰化物间氯苯基-
Bioenergetic functions in the membranes of Halobacterium halobium depend on respiration in the dark, and on two retinal pigments during illumination. The better known of these is bacteriorhodopsin [l], which is found in crystalline arrays (patches) covering as much as 50% of the cell surface. Bacteriorhodopsin is a light-dependent pump for protons, and it has been proposed [2-4] that the pH difference and particularly the electrical potential, which is created during illumination by proton extrusion across the cytoplasmic membrane, is the energizing folce for ATP synthesis. Illumination will indeed support the growth of bacteriorhodopsin-containing H. halobium under strictly anaerobic conditions [5].The second retinal pigment, present in smaller amounts in the halobacteria, is halorhodopsin. This pigment is a light-driven electrogenic pump for Na÷[6-8], and its spectral characteristics are somewhat different [9, 10] from those of bacteriorhodopsin. The presence of this pump is most easily recognized in cell envelope vesicles prepared from H. halobium strains lacking bacteriorhodopsin. Illumination of such vesicles results in uncoupler-facilitated passive proton uptake until a pH difference (acid inside) is balanced by a membrane potential (negative inside), so that the protonmotive force is zero [8]. Appropriately prepared vesicles from wild-type, bacteriorhodopsin-containing cells show both active and passive proton movements upon illumination [7, 8], the former appearing as efflux, the latter as influx. Proton conductors will tend to suppress proton efflux but enhance the influx. It appears therefore, that when present, both pumps are oriented in the outward direction in Abbreviations: CCCP, carbonyl cyanide metachlorophenyl-