Premium
Evidence for two calcium transport systems in the photosynthetic bacterium Chromatium vinosum
Author(s) -
Peach Cindy R.,
Cobb Andrea D.,
Smith James A.,
Knaff David B.
Publication year - 1986
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(86)81158-9
Subject(s) - ruthenium red , trifluoperazine , phenothiazine , antiporter , efflux , chemistry , ruthenium , calcium , biochemistry , biology , calmodulin , enzyme , membrane , catalysis , organic chemistry , pharmacology
Light‐dependent Ca 2+ efflux via the Ca 2+ /H + antiport in the photosynthetic purple sulfur bacterium Chromatium vinosum was inhibited by three phenothiazines: chlorpromazine; trifluoperazine and phenothiazine. The inhibitors had no effect on Ca 2+ uptake by C. vinosum in the dark nor any effect on the light‐dependent efflux of either Na + or Tl + catalyzed, respectively, by the C. vinosum Na + /H + or K + /H + antiports. Ruthenium red and LaCl 3 , neither of which inhibited light‐dependent Ca 2+ efflux in C. vinosum , markedly inhibited Ca 2+ uptake in the dark by C. vinosum cells. Ruthenium red had no effect on the uptake of either Na + or the K + analog T1 + by C. vinosum cells in the dark. These results have been interpreted in terms of two separate Ca 2+ transport systems in C. vinosum : (i) a phenothiazine‐sensitive and ruthenium red, La 3+ ‐insensitive Ca 2+ /H + antiport responsible for Ca 2+ efflux in the light; and (ii) a ruthenium red and La 3+ ‐sensitive but phenothiazine‐insensitive Ca 2+ uptake system.