We have proposed a model of the ATP hydrolytic sector of the clathrin- coated vesicle H+-ATPase wherein significant catalysis requires four subunits of molecular masses of 70, 58, 40, and 33 kDa (Xie, X.-S., and Stone, D. K. (1988) J. Biol. Chem. 263, 9859-9867). We have cloned and expressed the 40-kDa component in Escherichia coli and have purified the recombinant protein to homogeneity. This subunit lacks ATP hydrolytic capacity, but when reconstituted to a 40 kDa-depleted hydrolytic sector, there is a greater than 20-fold increase in calcium-activated, N- ethylmaleimide-sensitive ATP hydrolysis, indicating that this subunit is required for vacuolar-type proton pump function.
|Original language||English (US)|
|Number of pages||5|
|Journal||Journal of Biological Chemistry|
|State||Published - 1993|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology