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Schnizer R, Van Heeke G, Amaturo D, Schuster SM. Histidine-49 is necessary for the pH-dependent transition between active and inactive states of the bovine F1-ATPase inhibitor protein. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1292:241-8. [PMID: 8597569 DOI: 10.1016/0167-4838(95)00208-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The role of the histidyl residue at position 49 (H49) of the bovine mitochondrial F1-ATPase inhibitor protein (F1I) was examined by site-directed mutagenesis. Six amino acids (Q, E, K, V, L, and I) were substituted for H49 and the activities of the resulting inhibitor proteins were characterized with respect to pH. Each of the six mutations abolished the pH sensitivity which is characteristic of wild-type F1I. At pH 8.0 each of the mutations caused an increase in apparent maximum inhibition and a decrease in apparent Ki relative to wild type. At pH 6.7 the hydrophilic substitutions had little effect on apparent Ki, while the hydrophobic substitutions caused increases of 3.5- to 8.5-fold relative to wild type. The ratios of apparent Ki at pH 8.0 to apparent Ki at pH 6.7 were in the range of 0.5 to 1.6 for the mutants, whereas the wild-type value is 15.0. The mutations appear to shift the equilibrium between active and inactive conformations of F1I toward the active state. We find that H49 is required by F1I for sensitivity to pH and that it may facilitate the transition between active and inactive states of F1I. A possible role for H49 in the stabilization of the inactive state through participation in a multivalent complex with Zn2+ is also discussed.
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Affiliation(s)
- R Schnizer
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL 32610, USA
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2
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Stout JS, Partridge BE, Dibbern DA, Schuster SM. Peptide analogs of the beef heart mitochondrial F1-ATPase inhibitor protein. Biochemistry 1993; 32:7496-502. [PMID: 8338848 DOI: 10.1021/bi00080a022] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Peptide analogs which correspond to the conserved region of the natural ATPase inhibitor protein from beef heart, Candida utilis, and Saccharomyces cerevisiae mitochondria were synthesized by solid-phase methodologies and tested for ATPase inhibitory activity. These peptides were found to be potent inhibitors of F1-ATPase-catalyzed ATP hydrolysis in acidic reaction media, having I50 values of 1.1 +/- 0.4 microM, 10 +/- 5 microM, and 48 +/- 19 microM, respectively. These results closely match those obtained for the naturally occurring inhibitor proteins. Additional peptides that correspond to the beef heart beta-subunit near the binding site of the beef heart inhibitor protein and that possess a substantial homology with the conserved region of the inhibitor protein were synthesized. Several of these peptides were found to be inhibitors of the ATPase activity. The best inhibitor, with an I50 value of 20 +/- 3 microM, was the peptide resembling the beef heart beta-subunit comprising amino acids 394-413. This peptide most closely resembles the peptides derived from the conserved region of the inhibitor protein. The insertion of five glycine residues between the charge clusters in the beta-394-413 peptide resulted in a peptide which was able to stimulate the hydrolysis of ATP.
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Affiliation(s)
- J S Stout
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville 32610-0245
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Lopez-Mediavilla C, Vigny H, Godinot C. Docking the mitochondrial inhibitor protein IF1 to a membrane receptor different from the F1-ATPase beta subunit. EUROPEAN JOURNAL OF BIOCHEMISTRY 1993; 215:487-96. [PMID: 8344316 DOI: 10.1111/j.1432-1033.1993.tb18058.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Monoclonal antibodies reacting with the inhibitor protein (IF1) of the mitochondrial ATPase/ATP synthase complex did not modify the IF1-induced inhibition of soluble F1 ATPase activity. On the contrary, they increased the ATPase activity of inverted electron-transport particles without inducing a significant release of IF1 from these particles. This suggested that IF1 could be linked to a membrane protein when it was not inhibiting the ATPase activity. IF1 antibodies have been used to show that IF1 can bind not only to the beta subunit of F1-ATPase [Klein, G., Satre, M., Dianoux, A. C. & Vignais, P. V. (1981) Biochemistry 20, 1339-1344] but also to a protein present in the inner-mitochondrial membrane. The cross-linking of IF1 to this membrane protein gave a product of M(r) 15000-16000 that migrated differently from IF1 and from the dimer of IF1 using SDS/PAGE. When the cross-linked product was obtained by using a cleavable cross-linking reagent, the complex between IF1 and the docking protein was partly dissociated and free IF1 was recovered. Considering the molecular mass of IF1, this docking protein for IF1 has apparent M(r) 5000-6000. The complex between IF1 and this receptor protein can be detected in low amounts by antibodies against IF1 in the absence of cross-linking reagent. Since this complex remained in the pellet after treatment of the membrane with Triton X-100, it should be a membrane protein. Therefore, IF1 can bind not only to its inhibitory-binding site at the beta subunit of F1, but also to a non inhibitory site which is a membrane protein of approximate M(r) 5000-6000.
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Affiliation(s)
- C Lopez-Mediavilla
- Laboratoire de Biologie et Technologie, Université Claude Bernard de Lyon I, Villeurbanne, France
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Cox D, Matlib M. A role for the mitochondrial Na(+)-Ca2+ exchanger in the regulation of oxidative phosphorylation in isolated heart mitochondria. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)54024-2] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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5
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Yamada EW, Huzel NJ. Distribution of the ATPase inhibitor proteins of mitochondria in mammalian tissues including fibroblasts from a patient with Luft's disease. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1139:143-7. [PMID: 1535226 DOI: 10.1016/0925-4439(92)90093-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The mitochondrial ATPase inhibitor proteins--the Pullman-Monroy inhibitor (PMI) and the Ca(2+)-binding protein (CaBI)--have a wide distribution, both being present in mitochondria of bovine heart and kidney, rat liver and brain, two mitochondrial populations of rabbit skeletal muscle, and mitochondria from human fibroblasts and the human breast cancer cell line T-47-D. The ratio of CaBI to PMI was highest in heart and skeletal muscle mitochondria. The subsarcolemmal fraction of skeletal muscle had 2.6-times as much CaBI as did the intermyofibrillar. The ratio of CaBI to PMI in the mitochondria of the other normal tissues and fibroblasts was close to 1. In contrast, mitochondria from T-47D cells had 1.5-times as much PMI as CaBI whilst mitochondria from fibroblasts from a patient with Luft's disease showed a virtual lack of PMI. The specific ATPase, ATP-synthetase and succinate dehydrogenase activities of the Luft's mitochondria were, however, in the normal range. The specific ATP synthetase activity of the T-47D cells was significantly higher than normal. We conclude that tissues like heart and skeletal muscle which experience wide fluctuations in intracellular Ca2+ have a greater need for CaBI. Why lack of PMI could lead to 'loose' coupling of oxidative phosphorylation in skeletal muscle of Luft's patients, but not in fibroblasts is discussed.
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Affiliation(s)
- E W Yamada
- Department of Biochemistry and Molecular Biology, University of Manitoba, Winnipeg, Canada
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Sokolove PM, Kester MB, Westphal PA. Duramycin effects on the structure and function of heart mitochondria. II. Energy conversion reactions. Arch Biochem Biophys 1991; 287:180-5. [PMID: 1654802 DOI: 10.1016/0003-9861(91)90404-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The polypeptide antibiotic duramycin has been reported to interact selectively with phosphatidylethanolamine (PE) and monogalactosyldiacylglycerol (Navarro et al., 1985, Biochemistry 24, 4645-4650). PE is a major component of mitochondrial membranes. Duramycin was used to probe the role of PE in mitochondrial energy conversion reactions with the following results: (i) Duramycin uncoupled mitochondrial respiration, decreasing the respiratory control ratio to 1 at 5 microM. At concentrations of duramycin in excess of 10 microM, ADP addition inhibited electron transport. (ii) Duramycin inhibited oxidative phosphorylation (C50 less than 2 microM). (iii) Duramycin stimulated mitochondrial ATP hydrolysis modestly. The antibiotic was 7- to 16-fold less effective in this regard than concentrations of carbonylcyanide p-trifluoromethoxyphenylhydrazone (F-CCP) which produced comparable uncoupling. (iv) Duramycin inhibited uncoupled ATPase activity (C50 = 8 microM). Inhibition of the ATPase activity of intact mitochondria was blocked by 1 mM MgCl2 and 5 mM CaCl2; inhibition persisted in sub-mitochondrial particles assayed in the presence of 3 mM MgCl2. The effects on mitochondrial function of free fatty acids (FFA) and duramycin are similar in many respects. It is suggested that duramycin, like FFA, uncouples via a nonclassical mechanism, possibly by disrupting intramembrane H+ transfer between redox and ATPase complexes. In addition, interaction of duramycin, either direct or indirect, with the F0 moiety of the mitochondrial ATPase and with one or more components of the respiratory electron transport chain is proposed.
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Affiliation(s)
- P M Sokolove
- Department of Pharmacology & Experimental Therapeutics, University of Maryland Medical School, Baltimore 21201
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The calcium-binding ATPase inhibitor protein from bovine heart mitochondria. Purification and properties. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)37985-7] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Abstract
The mitochondrial ATP synthase/ATPase (F0F1 ATPase) is perhaps the most complex enzyme known. In animal systems it consists of a minimum of 11 different polypeptide chains, 10 (or more) of which appear to be essential for function, and 1 called the "ATPase inhibitor peptide" which is involved in regulation. Recent studies from a variety of laboratories indicate that the ATP synthase/ATPase complex is regulated by several interrelated factors including the thermodynamic poise of the proton gradient across the inner mitochondrial membrane; the ATPase inhibitor peptide; ADP (and/or ADP and Pi); divalent cations; and perhaps the redox state of SH groups on the F1 molecule. The central focus of this review is the ATPase inhibitor peptide. A model involving four distinct conformational states of F1 seems essential to account for the inhibitor's mode of action. The model depicts the ATPase inhibitor protein as acting at the asymmetric center of the F1 moiety. In addition, it accounts for the "unidirectional" role of the inhibitor peptide as a "down regulator" of ATP hydrolysis and for its binding/debinding dependence on the proton motive force and other regulatory factors. Finally, it is suggested that during any physiological process, where there is an energy demand followed by a resting phase, the F1 molecule may follow a "cyclic" path involving the four distinct conformational states of the enzyme.
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Yamada EW, Huzel NJ. Ca2+-binding properties of a unique ATPase inhibitor protein isolated from mitochondria of bovine heart and rat skeletal muscle. Cell Calcium 1985; 6:469-79. [PMID: 2936456 DOI: 10.1016/0143-4160(85)90022-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Previous studies showed that Ca2+ induced monomer to active dimer interconversion of a mitochondrial ATPase inhibitor protein from bovine heart or rat skeletal muscle (Yamada, E.W., Huzel, N.J. and Dickison, J.C. (1981) J. Biol. Chem. 256, 10203-10207). Initial equilibrium dialysis measurements of Ca2+ binding showed that this unique protein possesses three binding sites of high affinity with a maximum of one mol of Ca2+ bound/mol of protein monomer. Magnesium (1 mM) did not affect the first association constant but increased the second and third by about 1.2 and 1.5 fold, respectively. That the apparent association constants varied with concentration of protein monomer was in agreement with the self-associating nature of the protein. Scatchard plots at three concentrations of protein intersected at a molar ratio of about 0.5 (Ca2+/monomer). Ka1 and Ka2 values of 4.2 microM and 12.1 microM, respectively, were estimated by extra-polation of apparent constants to infinite dilution of protein. Ka3 (51.3 microM) was estimated by extrapolation of double reciprocal plots of apparent constants versus protein concentration to infinite levels of protein. A model for Ca2+ binding by this self-associating protein is described. Trifluoperazine had no effect on the activity of the inhibitor protein from either tissue.
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11
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Feinstein DL, Moudrianakis EN. Response of the adenosine triphosphatase activity of the soluble latent F1 enzyme from beef heart mitochondria to changes in Mg2+ and H+ concentrations. J Biol Chem 1984. [DOI: 10.1016/s0021-9258(17)43034-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Yamada EW, Huzel NJ. Isolation of two ATPase inhibitor proteins from mitochondria of rat skeletal muscle. Biosci Rep 1983; 3:947-54. [PMID: 6228264 DOI: 10.1007/bf01140664] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
An ATPase inhibitor protein was isolated from mitochondria of rat skeletal muscle by alkaline extraction and then was purified. It differed in definitive ways from the ATPase inhibitor protein isolated previously by Ca2+-stripping of submitochondrial particles of rat skeletal muscle. The two ATPase inhibitor proteins were shown to be present together in intact mitochondria.
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Fujimura K, Phillips DR. Calcium cation regulation of glycoprotein IIb-IIIa complex formation in platelet plasma membranes. J Biol Chem 1983. [DOI: 10.1016/s0021-9258(17)44449-8] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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14
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Pershadsingh HA, Martin AP, Vorbeck ML, Long JW, Stubbs EB. Ca2+-dependent depolarization of energized mitochondrial membrane potential by chlortetracycline (aureomycin). J Biol Chem 1982. [DOI: 10.1016/s0021-9258(18)33534-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Klein G, Satre M, Zaccai G, Vignais PV. Spontaneous aggregation of the mitochondrial natural ATPase inhibitor in salt solutions as demonstrated by gel filtration and neutron scattering. Application to the concomitant purification of the ATPase inhibitor and F1-ATPase. BIOCHIMICA ET BIOPHYSICA ACTA 1982; 681:226-32. [PMID: 6214274 DOI: 10.1016/0005-2728(82)90026-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
(1) The natural ATPase inhibitor (IF1) from beef heart mitochondria has a tendency to form aggregates in aqueous solutions. The extent of aggregation and the structure of the aggregates were assessed by gel filtration and small-angle neutron scattering. IF1 polymerization was found to depend on the salt concentrations, pH of the medium and concentration of IF1. The higher the salt concentration, the lower the aggregation state. Aggregation of IF1 was decreased at slightly acidic pH. It increased with the concentration of IF1 as expected from the law of mass action. (2) Neutron scattering showed the aggregation of IF1 in 2 M ammonium sulfate solutions. The predominant species is the dimer which has a somewhat elongated shape. (3) The Sephadex G-50 chromatography that is supposed to deprive beef heart submitochondrial particles of loosely bound IF1 (Racker, E. and Horstman, L.L. (1967) J. Biol. Chem. 242, 2547-2551) was shown to have a limited effectiveness as a trap for IF1. The reason was that IF1 released from the particles formed high molecular weight aggregates that were not separated from the membrane vesicles by Sephadex G-50 chromatography. (4) The above observations provide the basis for a simple method of purification of beef heart IF1 which combines the recovery of the supernatant from submitochondrial particles with the last three steps of the IF1 preparation described by Horstman and Racker (J. Biol. Chem. (1970) 265, 1336-1344). The particles recovered in the sediment were deprived of IF1 and could therefore be used for preparation of F1-ATPase. The advantage of this method is that both IF1 and F1-ATPase can be prepared from the same batch of mitochondria.
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A Ca2+-binding lipoprotein from submitochondrial particles of rat skeletal muscle or bovine heart. J Biol Chem 1982. [DOI: 10.1016/s0021-9258(19)68149-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Raymond Y, Shore G. Processing of the precursor for the mitochondrial enzyme, carbamyl phosphate synthetase. Inhibition by rho-aminobenzamidine leads to very rapid degradation (clearing) of the precursor. J Biol Chem 1981. [DOI: 10.1016/s0021-9258(19)69738-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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