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Functional identification of ATP‐driven Ca 2+ pump in the peribacteroid membrane of broad bean root nodules
Author(s) -
Andreev Igor M.,
Dubrovo Pavel N.,
Krylova Valeria V.,
Izmailov Stanislav F.
Publication year - 1999
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/s0014-5793(99)00262-8
Subject(s) - vanadate , ionophore , calcium , atpase , biochemistry , membrane , biology , chemistry , enzyme , organic chemistry
A Ca 2+ indicator arsenazo III was used to demonstrate calcium uptake activity of symbiosomes and the peribacteroid membrane (PBM) vesicles isolated from broad bean root nodules and placed in the medium containing ATP and Mg 2+ ions. This process was shown to be rapidly stopped by vanadate, completely reversed in the presence of the calcium ionophore A23187 but insensitive to agents abolishing electrical potential or pH difference across the PBM. The presence of an endogenous calcium pool within isolated symbiosomes and bacteroids was detected using a Ca 2+ indicator chlortetracycline. These results prove a primary active transport of Ca 2+ through the PBM of legume root nodules and provide the first functional identification of an ATP‐driven Ca 2+ ‐pump, most likely Mg 2+ ‐dependent Ca 2+ ‐translocating ATPase, in this membrane.