Assembly of the Mitochondrial Tim9–Tim10 Complex: A Multi-step Reaction with Novel Intermediates

Иванова, Е. М.; Jowitt, Thomas A.; Lu, Hui

doi:10.1016/j.jmb.2007.10.037

Cited by 25 publications

(36 citation statements)

References 33 publications

(46 reference statements)

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“…Oxidized WT and mutant Tim10 were purified as described previously in buffer AE (50 mM Tris, pH 7.4, 150 mM NaCl, 1 mM EDTA) [10,24]. Trx1 and Trr1 were purified as described previously [25], and followed by gel filtration (Superde Â 200 column).…”

Section: Methodsmentioning

confidence: 99%

Cytosolic Thioredoxin System Facilitates the Import of Mitochondrial Small Tim Proteins

Durigon

Wang

Pavia

et al. 2012

Free Radical Biology and Medicine

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Thiol-disulphide redox regulation has a key role during the biogenesis of mitochondrial intermembrane space (IMS) proteins. Only the Cys-reduced form of precursor proteins can be imported into mitochondria, which is followed by disulphide bond formation in the mitochondrial IMS. In contrast to the wealth of knowledge on the oxidation process inside mitochondria, little is known about how precursors are maintained in an importcompetent form in the cytosol. Here we provide the first evidence that the cytosolic thioredoxin system is required to maintain the IMS small Tim proteins in reduced forms and facilitate their mitochondrial import during respiratory growth.Keywords: redox regulation; mitochondrial import; thioredoxin; oxidoreductase; folding EMBO reports (2012) 13, 916-922.

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Section: Methodsmentioning

confidence: 99%

Cytosolic Thioredoxin System Facilitates the Import of Mitochondrial Small Tim Proteins

Durigon

Wang

Pavia

et al. 2012

Free Radical Biology and Medicine

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“…The SLS measurements were performed with a pneumatic drive Hi-Tech SFA-20 M apparatus in conjunction with a Cary Eclipse spectrofluorimeter (Varian, Polo Alto, USA) as previously described (Ivanova, Jowitt, and Lu 2008). To observe the binding of SSF to PAs, equal 140 μL volumes of PAs (22.4-74.6 μg/mL) and buffered SSF (224 μg/mL) were mixed at 25°C in the thermostated sample compartment containing a 280 μL quartz stopped-flow cuvette.…”

Section: Stopped-flow Light Scattering (Sls) and Dynamic Light Scattementioning

confidence: 99%

Binding of proanthocyanidins to soybean (Glycine max) seed ferritin inhibiting protein degradation by protease in vitro

Deng

Zhang

et al. 2011

Food Research International

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“…The mixing dead time was determined to be 6.8 Ϯ 0.5 ms using the dichloroindophenol and ascorbic acid test reaction (31). Both excitation and emission wavelengths were set at 680 nm, and the time-dependent change in scattering light at a 90°angle, perpendicular to the beam, was recorded (32). The kinetic data were curve-fitted with Origin 7.5 software (Micro Cal Inc.).…”

Section: Preparation Of Holo and Apo Pea Seed Ferritin And The Ep-mentioning

confidence: 99%

“…Light Scattering-Effects of EDTA and NaCl on ferritin aggregation induced by ferric ion were observed with the Cary Eclipse spectrofluorimeter at room temperature with both excitation and emission wavelengths set at 680 nm (32). The time-dependent change in scattering intensity was recorded upon mixing 96 Fe 2ϩ or Fe 3ϩ /shell with 2 ml of apoferritin in 100 mM Mops (pH 7.0).…”

Section: Preparation Of Holo and Apo Pea Seed Ferritin And The Ep-mentioning

confidence: 99%

Protein Association and Dissociation Regulated by Ferric Ion

et al. 2009

Journal of Biological Chemistry

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Iron stored in phytoferritin plays an important role in the germination and early growth of seedlings. The protein is located in the amyloplast where it stores large amounts of iron as a hydrated ferric oxide mineral core within its shell-like structure. The present work was undertaken to study alternate mechanisms of core formation in pea seed ferritin (PSF). The data reveal a new mechanism for mineral core formation in PSF involving the binding and oxidation of iron at the extension peptide (EP) located on the outer surface of the protein shell. This binding induces aggregation of the protein into large assemblies of ϳ400 monomers. The bound iron is gradually translocated to the mineral core during which time the protein dissociates back into its monomeric state. Either the oxidative addition of Fe 2؉ to the apoprotein to form Fe 3؉ or the direct addition of Fe 3؉ to apoPSF causes protein aggregation once the binding capacity of the 24 ferroxidase centers (48 Fe 3؉ /shell) is exceeded. When the EP is enzymatically deleted from PSF, aggregation is not observed, and the rate of iron oxidation is significantly reduced, demonstrating that the EP is a critical structural component for iron binding, oxidation, and protein aggregation. These data point to a functional role for the extension peptide as an iron binding and ferroxidase center that contributes to mineralization of the iron core. As the iron core grows larger, the new pathway becomes less important, and Fe 2؉ oxidation and deposition occurs directly on the surface of the iron core.The chemistry of iron and oxygen in a number of non-heme di-iron proteins has been a subject of intense interest because of their varied roles in oxygen activation and catalysis, substrate hydrolysis, oxygen transport, redox reactions, H 2 O 2 , and iron detoxification and iron storage. Di-iron centers have similar structural motifs consisting of a combination of carboxylate and histidine ligands that either bind or bridge the two metal ions of the di-nuclear active site; di-iron proteins containing these centers include methane monooxygenase, ribonucleotide reductase, rubrerythrin, stearoyl desaturase, purple acid phosphatase, hemerythrin, the Dps proteins, and ferritins (1-6). Despite their similar di-nuclear centers, each of these proteins fulfills a distinct biological role that seems to be mediated by the nature of the first and second coordination sphere of the di-iron center.Ferritins are a class of intracellular iron storage and detoxification proteins that facilitate the oxidation of iron by molecular oxygen or hydrogen peroxide to form a hydrous ferric oxide mineral core within their interiors (1-3). Rapid Fe 2ϩ oxidation occurs at the di-iron ferroxidase center located on the H-subunit of the mammalian protein. Unlike the H-chain, the more acidic L-subunit lacks the ferroxidase center but contains a putative nucleation site responsible for slower iron oxidation and mineralization (7). The shapes of both the H-and L-subunit are nearly cylindrical and composed of a four...

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Assembly of the Mitochondrial Tim9–Tim10 Complex: A Multi-step Reaction with Novel Intermediates

Cited by 25 publications

References 33 publications

Cytosolic Thioredoxin System Facilitates the Import of Mitochondrial Small Tim Proteins

Cytosolic Thioredoxin System Facilitates the Import of Mitochondrial Small Tim Proteins

Binding of proanthocyanidins to soybean (Glycine max) seed ferritin inhibiting protein degradation by protease in vitro

Protein Association and Dissociation Regulated by Ferric Ion

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