The bioenergetics of salt tolerance: Final report (2)
Studies on the physiology and molecular mechanism of light-driven chloride transport by halorhodopsin in the halobacteria are described. These studies focus on the ion-transport ATPase of halobacteria and the respiration-linked sodium transport system of the halotolerant bacterium, Bal. The results have provided insights into the role and functioning of ionic pumps. Chloride transport was shown to be an integral component of the overall ion circulation in halobacterial cells, one which maintains internal salt concentration and therefore cellular volume. A considerable amount of new information was gained about how halorhodopsin functions: its photointermediates, the nature of chloride-binding sites, the role of the deprotonation of the retinal Schiff-base, and how removal of most of the arginine residues affects (or rather, not affects) chloride-binding. Methods were adapted and developed for the study of membrane-bound halobacterial ATPase, its solubilization and (so far) partial purification. It was shown that in the salt-tolerant pseudomonad, Bal, the sodium-sensitive step in the respiratory chain is at the reduction of the semiquinone to quinol, as in another unrelated, but also salt-tolerant, marine microorganism. 17 refs., 1 fig.
- Research Organization:
- California Univ., Irvine (USA). Dept. of Physiology and Biophysics
- DOE Contract Number:
- AS03-80ER10637
- OSTI ID:
- 6860329
- Report Number(s):
- DOE/ER/10637-T5; ON: DE87006650
- Resource Relation:
- Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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