In:
Journal of Experimental Biology, The Company of Biologists, Vol. 172, No. 1 ( 1992-11-01), p. 123-135
Abstract:
Acidification of endomembrane compartments by the vacuolar-type H+-translocating ATPase (V-ATPase) is vital to the growth and development of plants. The V-ATPase purified from oat roots is a large complex of 650×10Mr that contains 10 different subunits of 70, 60,44,42, 36, 32, 29, 16, 13 and 12 × 103Mr. This set of ten polypeptides is sufficient to couple ATP hydrolysis to proton pumping after reconstitution of the ATPase into liposomes. Unlike some animal V-ATPases, the purified and reconstituted V-ATPase from oat is directly stimulated by Cl−. The peripheral complex of the ATPase includes the nucleotide-binding subunits of 70 and 60 × 103Mr and polypeptides of 44, 42, 36 and 29 × 103Mr. Six copies of the 16 × 103Mr proteolipid together with three other polypeptides are thought to make up the integral sector that forms the H+-conducting pathway. Release of the peripheral complex from the native membrane completely inactivates the pump; however, the peripheral subunits can be reassembled with the membrane sector to form a functional H+ pump. Comparison of V-ATPases from several plants indicates considerable variations in subunit composition. Hence, several forms of the V-ATPase may exist among, and probably within, plant species. At least four distinct cDNAs encode the 16 × 103Mr proteolipid subunit in oat. Multiple genes could encode different subtypes of the H+ pump that are regulated by the developmental stage and physiological function specific to the cell or tissue type.
Type of Medium:
Online Resource
ISSN:
0022-0949
,
1477-9145
DOI:
10.1242/jeb.172.1.123
Language:
English
Publisher:
The Company of Biologists
Publication Date:
1992
detail.hit.zdb_id:
1482461-9
SSG:
12
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