AVP2, a sequence-divergent, K{sup +}-insensitive H{sup +}-translocating inorganic pyrophosphatase from arabidopsis
Plant vacuolar H{sup +}-translocating inorganic pyrophosphatase have been considered to constitute a family of functionally and structurally monotonous intrinsic membrane proteins. Typified by AVPI from Arabidopsis, all characterized plant V-PPases share greater than 84% sequence identity and catalyze K{sup +}-stimulated H{sup +} translocation. Here the authors describe the molecular and biochemical characterization of AVP2, a sequence-divergent K{sup +}-insensitive, Ca{sup 2+}-hypersensitive V-PPase active in both inorganic pyrophosphate hydrolysis and H{sup +} translocation. The differences between AVP2 and AVP1 provide the first indication that plant V-PPase sequences from the same organism fall into two distinct categories. Phylogenetic analyses of these and other V-PPase sequences extend this principle by showing that AVP2, rather than being an isoform of AMP1, is but one representative of a novel category of AVP2-like (type 2) V-PPases that coexist with AVP1-like (type 1) V-PPases not only in plants, but also in apicomplexan protists such as the malarial parasite Plasmodium falciparum.
- Research Organization:
- Univ. of Pennsylvania, Philadelphia, PA (US)
- OSTI ID:
- 20062530
- Journal Information:
- Plant Physiology (Bethesda), Vol. 123, Issue 1; Other Information: PBD: May 2000; ISSN 0032-0889
- Country of Publication:
- United States
- Language:
- English
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