title: Voltage-dependent absorbance change of carotenoids in halophilic archaebacteria.
abstract: Membrane vesicles of wild-type Halobacterium sp. mex strain show a wavy absorbance change which has not been so far reported in halophilic archaebacteria. A white mutant strain lacking carotenoids did not show the wavy absorbance change. The wavy absorbance change in the range of 440-590 nm was induced by a red flash (600-640 nm), which photoexcited electrogenic ion pumps, mex bacteriorhodopsin and mex halorhodopsin but not carotenoids. The wavy change was also caused by K+ diffusion potentials without light. These results suggest that the wavy absorbance change in the membrane vesicles is the voltage-dependent absorbance change of the carotenoids.
authors.affiliation: Institute of Physical and Chemical Research (RIKEN) Wako, Japan.
authors.forename: S I
authors.initials: SI
authors.lastname: Seki
authors.forename: H
authors.initials: H
authors.lastname: Sasabe
authors.forename: H
authors.initials: H
authors.lastname: Tomioka
mesh_terms: D002338:Carotenoids / Q000737:chemistry*; D006217:Halobacterium / Q000737:chemistry* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008027:Light; D008564:Membrane Potentials; D009154:Mutation
chemical_list: D002338:Carotenoids