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Title: Light-dependent delta pH and membrane potential changes in halobacterial vesicles coupled to sodium transport

Abstract

Bacteriorhodopsin and Halorhodopsin present in Halobacterium halobium strains have been investigated in relation to Na/sup +//H/sup +/ exchange in isolated cell envelope vesicles. Upon illumination, these retinal proteins result in extrusion of sodium ions by either an electrogenic Na/sup +//Ha/sup +/ antiporter and/or a direct sodium pump. Since a molecular characterization of these mechanism(s) of sodium extrusion has not yet been realized, it was of interest to measure directly the light- and sodium-dependent changes in delta pH and membrane potential under nearly identical conditions in S9 and R1mR cell membrane vesicles to gain information on the relation of these retinal proteins to sodium extrusion. These activities were evaluated in terms of their dependence on light intensity, and on the inhibitory effect of chemical modifiers of carboxyl groups (carbodiimides); electroneutral exchanges (monensin and triphenyltin); digitoxin and some analogues; and phloretin. Under most of the conditions and treatments employed, light- and sodium-dependent delta pH led to similar effects in both membrane vesicle types. Hence, it is concluded that the delta pH and delta psi which arise from sodium transport occur by either a single mechanism or by one which shares common features.

Authors:
; ;
Publication Date:
Research Org.:
Membrane Bioenergetics Group, Lawrence Berkeley Laboratory, University of California, Berkeley, California
OSTI Identifier:
6817152
Resource Type:
Journal Article
Journal Name:
Membr. Biochem.; (United States)
Additional Journal Information:
Journal Volume: 4:3
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; SODIUM; MEMBRANE TRANSPORT; BIOCHEMICAL REACTION KINETICS; BIOLOGICAL PATHWAYS; MEMBRANES; PH VALUE; PHOTOSYNTHETIC BACTERIA; VISIBLE RADIATION; ALKALI METALS; ELECTROMAGNETIC RADIATION; ELEMENTS; KINETICS; METALS; RADIATIONS; REACTION KINETICS; 550200* - Biochemistry; 550700 - Microbiology

Citation Formats

Kamo, N, Racanelli, T, and Packer, L. Light-dependent delta pH and membrane potential changes in halobacterial vesicles coupled to sodium transport. United States: N. p., 1982. Web. doi:10.3109/09687688209065430.
Kamo, N, Racanelli, T, & Packer, L. Light-dependent delta pH and membrane potential changes in halobacterial vesicles coupled to sodium transport. United States. https://doi.org/10.3109/09687688209065430
Kamo, N, Racanelli, T, and Packer, L. 1982. "Light-dependent delta pH and membrane potential changes in halobacterial vesicles coupled to sodium transport". United States. https://doi.org/10.3109/09687688209065430.
@article{osti_6817152,
title = {Light-dependent delta pH and membrane potential changes in halobacterial vesicles coupled to sodium transport},
author = {Kamo, N and Racanelli, T and Packer, L},
abstractNote = {Bacteriorhodopsin and Halorhodopsin present in Halobacterium halobium strains have been investigated in relation to Na/sup +//H/sup +/ exchange in isolated cell envelope vesicles. Upon illumination, these retinal proteins result in extrusion of sodium ions by either an electrogenic Na/sup +//Ha/sup +/ antiporter and/or a direct sodium pump. Since a molecular characterization of these mechanism(s) of sodium extrusion has not yet been realized, it was of interest to measure directly the light- and sodium-dependent changes in delta pH and membrane potential under nearly identical conditions in S9 and R1mR cell membrane vesicles to gain information on the relation of these retinal proteins to sodium extrusion. These activities were evaluated in terms of their dependence on light intensity, and on the inhibitory effect of chemical modifiers of carboxyl groups (carbodiimides); electroneutral exchanges (monensin and triphenyltin); digitoxin and some analogues; and phloretin. Under most of the conditions and treatments employed, light- and sodium-dependent delta pH led to similar effects in both membrane vesicle types. Hence, it is concluded that the delta pH and delta psi which arise from sodium transport occur by either a single mechanism or by one which shares common features.},
doi = {10.3109/09687688209065430},
url = {https://www.osti.gov/biblio/6817152}, journal = {Membr. Biochem.; (United States)},
number = ,
volume = 4:3,
place = {United States},
year = {Fri Jan 01 00:00:00 EST 1982},
month = {Fri Jan 01 00:00:00 EST 1982}
}