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The 32 kDa tonoplast polypeptide D i associated with the V0‐type H + ‐ATPase of Mesembryanthemum crystallinum L. in the CAM state: A proteolytically processed subunit B?
Author(s) -
Zhigang An,
Löw Rainer,
Rausch Thomas,
Lüttge Ulrich,
Ratajczak Rafael
Publication year - 1996
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(96)00556-x
Subject(s) - mesembryanthemum crystallinum , protein subunit , atpase , v atpase , vacuole , biochemistry , chemistry , biology , crassulacean acid metabolism , enzyme , cytoplasm , gene , photosynthesis
In the facultative halophyte Mesembryanthemum crystallinum , the salt‐ or age‐induced transition to crassulacean acid metabolism (CAM) leads to the occurrence of a tonoplast‐bound 32 kDa polypeptide (D i ). The alignment of its N‐terminal protein sequence with protein sequences of recently cloned higher plant V‐ATPase B‐subunits indicates that D i may be derived from subunit B by proteolytic removal of a protein fragment of about 20 kDa from its N‐terminus. Furthermore, an antiserum directed against D i cross‐reacts with subunit B from Nicotiana tabacum . It inhibits both proton pumping and ATP hydrolysis of the holoenzyme in M. crystallinum . As D i remains firmly attached to the holoenzyme the proteolytic processing may have functional implications.