Molecular structure of the 8.0 kDa subunit of cytochrome-c reductase from potato and its Δψ-dependent import into isolated mitochondria

AbstractThe cytochrome-c reductase (EC 1.10.2.2) of the mitochondrial respiratory chain couples electron transport from ubiquinol to cytochrome c with proton translocation across the inner mitochondrial membrane. The enzyme from potato was shown to be composed of 10 subunits. Isolation and characterization of cDNA clones for the second smallest subunit reveal an open reading frame of 216 bp encoding a protein of 8.0 kDa. The protein exhibits similarities to a 7.2/7.3 kDa subunit of cytochrome-c reductase from bovine and yeast, that is localized on the intermembrane space side of the enzyme complex. It also shows similarity to a previously unidentified 7.8 kDa protein of cytochrome-c reductase from Euglena. The potato 8.0 kDa protein has a segmental structure, as its sequence can be devided into four parts, each comprising a central Arg-(Xaa)5-Val motif. N-terminal sequencing of the mature 8.0 kDa protein indicates the absence of a cleavable mitochondrial targeting sequence. Import of the in vitro synthesized 8.0 kDa protein into isolated potato mitochondria confirms the lack of a presequence and reveals a dependence of the transport on the membrane potatial Δψ across the inner mitochondrial membrane. These features are unique among the intermembrane space proteins known so far

Introduction to the AfricaGEO 2018 Conference Special Issue of the South African Journal of Geomatics

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Blue native DIGE as a tool for comparative analyses of protein complexes

Differential gel electrophoresis (DIGE) is based on pre-labeling of different protein fractions and their subsequent co-electrophoresis in a single gel. Cyanine based "CyDye DIGE Fluor minimal dyes" are used for the labeling reaction and 2D IEF/SDS PAGE is the preferential electrophoresis system for protein separation. The DIGE technology allows elimination of inconsistencies based on gel to gel variations and furthermore allows exact quantification of proteins separated by gel electrophoresis. Here we report applications of the DIGE technology in combination with another 2D gel system, Blue native/SDS PAGE. "Blue native DIGE" offers (i) systematic and quantitative comparison of protein complexes of related protein fractions, (ii) structural investigation of protein complexes, (iii) assignment of protein complexes to subcellular fractions like organelles and (iv) electrophoretic mapping of isoforms of subunits of protein complexes with respect to a larger proteome. The potential of "Blue native DIGE" is illustrated by analysis of organellar fractions from the plant Arabidopsis thaliana and the alga Polytomella. Use of the DIGE technology for topological investigations is discussed

New insights into the co-evolution of cytochrome c reductase and the mitochondrial processing peptidase

The mitochondrial processing peptidase (MPP) is a heterodimeric enzyme that forms part of the cytochrome c reductase complex from higher plants. Mitochondria from mammals and yeast contain two homologous enzymes: (i) an active MPP within the mitochondrial matrix and (ii) an inactive MPP within the cytochrome c reductase complex. To elucidate the evolution of MPP, the cytochrome c reductase complexes from lower plants were isolated and tested for processing activity. Mitochondria were prepared from the staghorn fern Platycerium bifurcatum, from the horsetail Equisetum arvense, and from the colorless algae Polytomella, and cytochrome c reductase complexes were purified by a micro-isolation procedure based on Blue-native polyacrylamide gel electrophoresis and electroelution. This is the first report on the subunit composition of a respiratory enzyme complex from a fern or a horsetail. The cytochrome c reductase complexes from P. bifurcatum and E. arvense are shown to efficiently process mitochondrial precursor proteins, whereas the enzyme complex from Polytomella lacks proteolytic activity. An evolutionary model is suggested that assumes a correlation between the presence of an active MPP within the cytochrome c reductase complex and the occurrence of chloroplasts

Unique composition of the preprotein translocase of the outer mitochondrial membrane from plants

Transport of most nuclear encoded mitochondrial proteins into mitochondria is mediated by heteropolymeric translocases in the membranes of the organelles. The translocase of the outer mitochondrial membrane (TOM) was characterized in fungi, and it was shown that TOM from yeast comprises nine different subunits. This publication is the first report on the preparation of the TOM complex from plant mitochondria. The protein complex from potato was purified by (a) blue native polyacrylamide gel electrophoresis and (b) by immunoaffinity chromatography. On blue native gels, the potato TOM complex runs close to cytochrome c oxidase at 230 kDa and hence only comprises about half of the size of fungal TOM complexes. Analysis of the TOM complex from potato by SDS-polyacrylamide gel electrophoresis allows separation of seven different subunits of 70, 36, 23, 9, 8, 7, and 6 kDa. The 23-kDa protein is identical to the previously characterized potato TOM20 receptor, as shown by in vitro assembly of this protein into the 230kDa complex, by immunoblotting and by direct protein sequencing. Partial amino acid sequence data of the other subunits allowed us to identify sequence similarity between the 36-kDa protein and fungal TOM40. Sequence analysis of cDNAs encoding the 7-kDa protein revealed significant sequence hornology of this protein to TOM7 from yeast. However, potato TOM7 has a N-terminal extension, which is very rich in basic amino acids. Counterparts to the TOM22 and TOM37 proteins from yeast seem to be absent in the potato TOM complex, whereas an additional low molecular mass subunit occurs. Functional implications of these findings are discussed

Efficacy and Safety of Biosimilar FYB201 Compared with Ranibizumab in Neovascular Age-Related Macular Degeneration.

Abstract Purpose This trial was conducted to investigate the clinical equivalence of the proposed biosimilar FYB201 and reference ranibizumab in patients with treatment-naive, subfoveal choroidal neovascularization caused by neovascular age-related macular degeneration (nAMD). Design This was a prospective, multicenter, evaluation-masked, parallel-group, 48-week, phase III randomized study. Participants A total of 477 patients were randomly assigned to receive FYB201 (n = 238) or reference ranibizumab (n = 239). Methods Patients received FYB201 or ranibizumab 0.5 mg by intravitreal injection in the study eye every four weeks. Main Outcome Measures The primary end point was change from baseline in best corrected visual acuity (BCVA) by Early Treatment Diabetic Retinopathy Study (ETDRS) letters at 8 weeks prior to the third monthly intravitreal injection. Biosimilarity of FYB201 to its originator was assessed via a two-sided equivalence test, with an equivalence margin in BCVA of 3 ETDRS letters. Results BCVA improved in both groups, with a mean improvement of +5.1 (FYB201) and +5.6 (reference ranibizumab) ETDRS letters at week 8. The analysis of covariance (ANCOVA) least squares mean difference for the change from baseline between FYB201 and reference ranibizumab was –0.4 ETDRS letters with a 90% confidence interval (CI) of –1.6 to 0.9. Primary end point was met as the 90% CI was within the predefined equivalence margin. Adverse events were comparable between treatment groups. Conclusions FYB201 is biosimilar to reference ranibizumab in terms of clinical efficacy and ocular and systemic safety in the treatment of patients with nAMD

Lambda production in 40 A GeV/c Pb-Au collisions

During the 1999 lead run, CERES has measured hadron and electron-pair production at 40 A GeV/c beam momentum with the spectrometer upgraded by the addition of a radial TPC. Here the analysis of lambda and antilambda will be presented.Comment: 8 pages, 8 figures. 6th International Conference on Strange Quarks in Matter, Frankfurt 200

Trapped Rydberg Ions: From Spin Chains to Fast Quantum Gates

We study the dynamics of Rydberg ions trapped in a linear Paul trap, and discuss the properties of ionic Rydberg states in the presence of the static and time-dependent electric fields constituting the trap. The interactions in a system of many ions are investigated and coupled equations of the internal electronic states and the external oscillator modes of a linear ion chain are derived. We show that strong dipole-dipole interactions among the ions can be achieved by microwave dressing fields. Using low-angular momentum states with large quantum defect the internal dynamics can be mapped onto an effective spin model of a pair of dressed Rydberg states that describes the dynamics of Rydberg excitations in the ion crystal. We demonstrate that excitation transfer through the ion chain can be achieved on a nanosecond timescale and discuss the implementation of a fast two-qubit gate in the ion chain.Comment: 26 pages, 9 figure

Многокомпонентные термины сферы автомобилестроения: структура и способы перевода с английского языка на русский

Работа нацелена на выявление структурных особенностей многокомпонентных терминов сферы автомобилестроения и особенностей их перевода с английского языка на русский. В результате исследования были выявлены формально-структурные модели английских многокомпонентных терминов, определены основные ядерные термины, участвующие в процессе терминодеривации. Были выявлены основные способы перевода многокомпонентных терминов с английского языка на русский язык, сделаны выводы об особенностях перевода многокомпонентных терминов в зависимости от их формально-структурных моделей.The thesis is aimed at revealing the structural features of multi-component terms of the automotive industry and the features of their translation from English into Russian. Research resulrs: formal structural models of English multicomponent terms have been identified, the most representative nuclear terms participating in the term-derivation process have been identified.The most efficient ways of translation of multi-component terms from English into Russian have been identified, the relation between the way multi-component terms were translated and its formal structure have been traced

Peculiar Type II Supernovae from Blue Supergiants

The vast majority of Type II supernovae (SNe) are produced by red supergiants (RSGs), but SN 1987A revealed that blue supergiants (BSGs) can produce members of this class as well, albeit with some peculiar properties. This best studied event revolutionized our understanding of SNe, and linking it to the bulk of Type II events is essential. We present here optical photometry and spectroscopy gathered for SN 2000cb, which is clearly not a standard Type II SN and yet is not a SN 1987A analog. The light curve of SN 2000cb is reminiscent of that of SN 1987A in shape, with a slow rise to a late optical peak, but on substantially different time scales. Spectroscopically, SN 2000cb resembles a normal SN II but with ejecta velocities that far exceed those measured for SN 1987A or normal SNe II, above 18000 km/s for H-alpha at early times. The red colours, high velocities, late photometric peak, and our modeling of this object all point toward a scenario involving the high-energy explosion of a small-radius star, most likely a BSG, producing 0.1 solar masses of Ni-56. Adding a similar object to the sample, SN 2005ci, we derive a rate of about 2% of the core-collapse rate for this loosely defined class of BSG explosions.Comment: Accepted to MNRAS on March 14, 201