The respiratory chain of the halophilic anoxygenic purple bacterium Rhodospirillum sodomense
| 详细信息 | 推荐本文 | |
- 作者：Patrizia Bonora ; Ilaria Principi ; Alejandro Hochkoeppler ; Roberto Borghese and D. Zannoni
- 关键词：Key words Branched respiratory chain ; Chemoheterotrophic growth ; Cytochromes ; Halophilic purple nonsulfur bacteria ; Rhodospirillum sodomense
- 刊名：Archives of Microbiology
- 出版时间：November 1998
- 出版年：1998
- 期刊代码：22_0302-8933
- 类别：bio
- 卷：170
- 期：6
- 页码：435-441
- 数据来源：sp
摘要
The halophilic purple nonsulfur bacterium Rhodospirillum sodomense has been previously described as an obligate phototroph that requires yeast extract and a limited number of organic compounds for photoheterotrophic growth. In this work, we report on chemoheterotrophic growth of R. sodomense in media containing either acetate or succinate supplemented with 0.3–0.5%yeast extract. Plasma membranes isolated from cells grown aerobically in the dark contained three b-type and three c-type membrane-bound cytochromes with E m,7 of +171 卤 10, +62 卤 10 and –45 卤 13 mV (561–575 nm), and +268 卤 6, +137 卤 10 and –43 卤 12 mV (551–540 nm). A small amount of a soluble c-type cytochrome with a mol. mass of 15 kDa (E m,7≥ +150 mV) was identified. Spectroscopic and immunological methods excluded the presence of cytochrome of the c 2 class and high-potential iron-sulfur proteins. Inhibitory studies indicated that only 60–70%of the respiratory activity was blocked by low concentrations of cyanide, antimycin A, and myxothiazol (10, 0.1, and 0.2 μM, respectively). These results were interpreted to show that the oxidative electron transport chain of R. sodomense is branched, leads to a quinol oxidase that is fully blocked by 1 mM cyanide and that is involved in light-dependent oxygen reduction, and leads to a cytochrome c oxidase that is inhibited by 10 μM cyanide. These features taken together suggest that R. sodomense differs from the closely related species Rhodospirillum salinarum and from other species of the genus Rhodospirillum in that it contains multiple membrane-bound cytochromes c.