Altered plasma membrane H(+)-ATPase from the Dio-9-resistant pma1-2 mutant of Schizosaccharomyces pombe.
(1992) European journal of biochemistry / FEBS — Vol. 209, n° 1, p. 275-279 (1992)
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- Abstract
- The pma1-2 mutation affecting the plasma membrane H(+)-ATPase of Schizosaccharomyces pombe has been selected for resistance to the antibiotic Dio-9. In membrane fractions purified from glucose-starved cells, the mutant ATPase activity is reduced by 96%, is insensitive to inhibition by vanadate and has a pH profile displaced in the acidic pH range when compared to the wild type. The maximum velocity of the H(+)-ATPase activity of plasma membranes from glucose-activated pma1-2 cells is activated 20-fold. This is in striking contrast with the wild-type ATPase activity, the maximal velocity of which is not affected by glucose. However, similar to the wild-type enzyme, glucose activation of the pma1-2 mutant H(+)-ATPase reduces the Km for MgATP 9-2 mM and shifts the optimal pH from 4.8 to 6.0-6.5. The pma1-2 mutation modifies Lys250 to a threonine, which is highly conserved in fungal and plant H(+)-ATPases. These results, compared to those reported for mutations of neighbour residues in yeast or mammalian P-type ATPases, suggest that Lys250 could play a significant role, not only in phosphate binding and/or in the E1P-E2P conformational isomerisation, but also in glucose activation of the H(+)-ATPase.
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Ghislain, M., De Sadeleer, M., & Goffeau, A. (1992). Altered plasma membrane H(+)-ATPase from the Dio-9-resistant pma1-2 mutant of Schizosaccharomyces pombe. European journal of biochemistry / FEBS, 209(1), 275-279. https://doi.org/10.1111/j.1432-1033.1992.tb17286.x (Original work published 1992)