The α/β subunit interaction in H+-ATPase (ATP synthase)

An Escherichia coli α subunit mutation (Arg-α296 → Cys) restores coupling efficiency to the deleterious β subunit mutant (Ser-β174 → Phe)

Hiroshi Omote, Mi Yeon Park, Masatomo Maeda, Masamitsu Futai

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23 Citations (Scopus)

Abstract

The Ser-β174 residue of the Escherichia coli H+-ATPase β subunit has been shown to be near the catalytic site together with Gly-β149, Gly-β172, Glu-β192, and Val-β198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-β174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-β174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (∼10% of the wild type). The defective energy coupling of the Phe-β174 mutant was suppressed by the second mutation (Arg-α296 → Cys) in the α subunit. The Cys-α296/Phe-β174 mutant had essentially the same membrane ATPase activity as the Phe-β174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the α/β interaction, especially that between the regions near Arg-α296 and Ser-β174, for energy coupling in the H+-ATPase. The 2 residues (Ser-β174 and Arg-α296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the α subunit of Cys-α296/Phe-β174 or Cys-α296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.

Original languageEnglish
Pages (from-to)10265-10269
Number of pages5
JournalJournal of Biological Chemistry
Volume269
Issue number14
Publication statusPublished - Apr 8 1994
Externally publishedYes

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Proton-Translocating ATPases
Escherichia coli
Adenosine Triphosphatases
Adenosine Triphosphate
Mutation
Enzyme activity
Catalysis
Enzymes
Ethylmaleimide
Catalytic Domain
Membranes

ASJC Scopus subject areas

  • Biochemistry

Cite this

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title = "The α/β subunit interaction in H+-ATPase (ATP synthase): An Escherichia coli α subunit mutation (Arg-α296 → Cys) restores coupling efficiency to the deleterious β subunit mutant (Ser-β174 → Phe)",
abstract = "The Ser-β174 residue of the Escherichia coli H+-ATPase β subunit has been shown to be near the catalytic site together with Gly-β149, Gly-β172, Glu-β192, and Val-β198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-β174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-β174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (∼10{\%} of the wild type). The defective energy coupling of the Phe-β174 mutant was suppressed by the second mutation (Arg-α296 → Cys) in the α subunit. The Cys-α296/Phe-β174 mutant had essentially the same membrane ATPase activity as the Phe-β174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the α/β interaction, especially that between the regions near Arg-α296 and Ser-β174, for energy coupling in the H+-ATPase. The 2 residues (Ser-β174 and Arg-α296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the α subunit of Cys-α296/Phe-β174 or Cys-α296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.",
author = "Hiroshi Omote and Park, {Mi Yeon} and Masatomo Maeda and Masamitsu Futai",
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TY - JOUR

T1 - The α/β subunit interaction in H+-ATPase (ATP synthase)

T2 - An Escherichia coli α subunit mutation (Arg-α296 → Cys) restores coupling efficiency to the deleterious β subunit mutant (Ser-β174 → Phe)

AU - Omote, Hiroshi

AU - Park, Mi Yeon

AU - Maeda, Masatomo

AU - Futai, Masamitsu

PY - 1994/4/8

Y1 - 1994/4/8

N2 - The Ser-β174 residue of the Escherichia coli H+-ATPase β subunit has been shown to be near the catalytic site together with Gly-β149, Gly-β172, Glu-β192, and Val-β198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-β174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-β174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (∼10% of the wild type). The defective energy coupling of the Phe-β174 mutant was suppressed by the second mutation (Arg-α296 → Cys) in the α subunit. The Cys-α296/Phe-β174 mutant had essentially the same membrane ATPase activity as the Phe-β174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the α/β interaction, especially that between the regions near Arg-α296 and Ser-β174, for energy coupling in the H+-ATPase. The 2 residues (Ser-β174 and Arg-α296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the α subunit of Cys-α296/Phe-β174 or Cys-α296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.

AB - The Ser-β174 residue of the Escherichia coli H+-ATPase β subunit has been shown to be near the catalytic site together with Gly-β149, Gly-β172, Glu-β192, and Val-β198 (Iwamoto, A., Park, M.-Y., Maeda, M., and Futai, M. (1993) J. Biol. Chem. 268, 3156-3160). In this study, we introduced various residues at position 174 and found that the larger the side chain volume of the residue introduced, the lower the enzyme activity became. The Phe-β174 mutant was defective in energy coupling between catalysis and transport, whereas the Leu-β174 mutant could couple efficiently, although both mutants had essentially the same ATPase activities (∼10% of the wild type). The defective energy coupling of the Phe-β174 mutant was suppressed by the second mutation (Arg-α296 → Cys) in the α subunit. The Cys-α296/Phe-β174 mutant had essentially the same membrane ATPase activity as the Phe-β174 single mutant when assayed under the conditions that stabilize the double mutant enzyme. These results indicate the importance of the α/β interaction, especially that between the regions near Arg-α296 and Ser-β174, for energy coupling in the H+-ATPase. The 2 residues (Ser-β174 and Arg-α296) may be located nearby at the interface of the two subunits. About 1 mol of N-[14C]ethylmaleimide could bind to 1 mol of the α subunit of Cys-α296/Phe-β174 or Cys-α296 mutant ATPase, but could not inhibit the enzyme activity. This is the first intersubunit mutation/suppression approach to ATPase catalysis and its energy coupling.

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