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Biochimica Et Biophysica Acta.... Oct 2022The superoxide anion - molecular oxygen reduced by a single electron - is produced in large amounts by enzymatic and adventitious reactions. It can perform a range of...
The superoxide anion - molecular oxygen reduced by a single electron - is produced in large amounts by enzymatic and adventitious reactions. It can perform a range of cellular functions, including bacterial warfare and iron uptake, signalling and host immune response in eukaryotes. However, it also serves as precursor for more deleterious species such as the hydroxyl anion or peroxynitrite and defense mechanisms to neutralize superoxide are important for cellular health. In addition to the soluble proteins superoxide dismutase and superoxide reductase, recently the membrane embedded diheme cytochrome b (CybB) from E. coli has been proposed to act as a superoxide:quinone oxidoreductase. Here, we confirm superoxide and cellular ubiquinones or menaquinones as natural substrates and show that quinone binding to the enzyme accelerates the reaction with superoxide. The reactivity of the substrates is in accordance with the here determined midpoint potentials of the two b hemes (+48 and -23 mV / NHE). Our data suggest that the enzyme can work near the diffusion limit in the forward direction and can also catalyse the reverse reaction efficiently under physiological conditions. The data is discussed in the context of described cytochrome b proteins and potential physiological roles of CybB.
Topics: Bacteria; Cytochromes b; Escherichia coli; Oxidoreductases; Superoxides
PubMed: 35671795
DOI: 10.1016/j.bbabio.2022.148583 -
Scientific Reports Mar 2016Haemosporida parasites of even-toed ungulates are diverse and globally distributed, but since their discovery in 1913 their characterization has relied exclusively on...
Haemosporida parasites of even-toed ungulates are diverse and globally distributed, but since their discovery in 1913 their characterization has relied exclusively on microscopy-based descriptions. In order to bring molecular approaches to bear on the identity and evolutionary relationships of ungulate malaria parasites, we conducted Plasmodium cytb-specific nested PCR surveys using blood from water buffalo in Vietnam and Thailand, and goats in Zambia. We found that Plasmodium is readily detectable from water buffalo in these countries, indicating that buffalo Plasmodium is distributed in a wider region than India, which is the only area in which buffalo Plasmodium has been reported. Two types (I and II) of Plasmodium sequences were identified from water buffalo and a third type (III) was isolated from goat. Morphology of the parasite was confirmed in Giemsa-reagent stained blood smears for the Type I sample. Complete mitochondrial DNA sequences were isolated and used to infer a phylogeny in which ungulate malaria parasites form a monophyletic clade within the Haemosporida, and branch prior to the clade containing bird, lizard and other mammalian Plasmodium. Thus it is likely that host switching of Plasmodium from birds to mammals occurred multiple times, with a switch to ungulates independently from other mammalian Plasmodium.
Topics: Animals; Buffaloes; Cytochromes b; Female; Genes, Protozoan; Malaria; Male; Phylogeny; Plasmodium; Protozoan Proteins; Sequence Analysis, DNA
PubMed: 26996979
DOI: 10.1038/srep23230 -
Communications Biology Sep 2022Mammalian cytochrome b (cyt b) and cytochrome b reductase (bR) are electron carrier proteins for membrane-embedded oxidoreductases. Both bR and cyt b have a cytosolic...
Mammalian cytochrome b (cyt b) and cytochrome b reductase (bR) are electron carrier proteins for membrane-embedded oxidoreductases. Both bR and cyt b have a cytosolic domain and a single transmembrane (TM) helix. The cytosolic domains of bR and cyt b contain cofactors required for electron transfer, but it is not clear if the TM helix has function beyond being an anchor to the membrane. Here we show that bR and cyt b form a stable binary complex, and so do cyt b and stearoyl-CoA desaturase-1 (SCD1). We also show that bR, cyt b and SCD1 form a stable ternary complex. We demonstrate that the TM helices are required for the assembly of stable binary and ternary complexes where electron transfer rates are greatly enhanced. These results reveal a role of the TM helix in cyt b and bR, and suggest that an electron transport chain composed of a stable ternary complex may be a general feature in membrane-embedded oxidoreductases that require cyt b and bR.
Topics: Animals; Cytochromes b; Electron Transport; Electrons; Mammals; Oxidoreductases
PubMed: 36097052
DOI: 10.1038/s42003-022-03882-z -
Chemical Reviews Apr 2018There are two types of electron bifurcation (EB), either quinone- or flavin-based (QBEB/FBEB), that involve reduction of a quinone or flavin by a two-electron transfer... (Review)
Review
There are two types of electron bifurcation (EB), either quinone- or flavin-based (QBEB/FBEB), that involve reduction of a quinone or flavin by a two-electron transfer and two reoxidations by a high- and low-potential one-electron acceptor with a reactive semiquinone intermediate. In QBEB, the reduced low-potential acceptor (cytochrome b) is exclusively used to generate ΔμH. In FBEB, the "energy-rich" low-potential reduced ferredoxin or flavodoxin has dual function. It can give rise to ΔμH/Na via a ferredoxin:NAD reductase (Rnf) or ferredoxin:proton reductase (Ech) or conducts difficult reductions such as CO to CO. The QBEB membrane complexes are similar in structure and function and occur in all domains of life. In contrast, FBEB complexes are soluble and occur only in strictly anaerobic bacteria and archaea (FixABCX being an exception). The FBEB complexes constitute a group consisting of four unrelated families that contain (1) electron-transferring flavoproteins (EtfAB), (2) NAD(P)H dehydrogenase (NuoF homologues), (3) heterodisulfide reductase (HdrABC) or HdrABC homologues, and (4) NADH-dependent ferredoxin:NADP reductase (NfnAB). The crystal structures and electron transport of EtfAB-butyryl-CoA dehydrogenase and NfnAB are compared with those of complex III of the respiratory chain (cytochrome bc), whereby unexpected common features have become apparent.
Topics: Archaea; Bacteria; Cytochromes b; Electron Transport; Electron-Transferring Flavoproteins; Ferredoxin-NADP Reductase; Flavins; Flavoproteins; NADPH Dehydrogenase; Oxidation-Reduction; Oxidoreductases; Protein Conformation; Quinones; Thermodynamics
PubMed: 29561602
DOI: 10.1021/acs.chemrev.7b00707 -
Revista Da Sociedade Brasileira de... 2022Incidence of Cutaneous Leishmaniasis as an infectious and neglected disease is increasing, for the diagnosis of which several traditional methods and conventional PCR...
BACKGROUND
Incidence of Cutaneous Leishmaniasis as an infectious and neglected disease is increasing, for the diagnosis of which several traditional methods and conventional PCR techniques have been developed, employing different genes for species identification.
METHODS
Leishmania parasites were sampled, DNA was extracted, and new specific and sensitive primers were designed. Two ITS-rDNA and Cyt b genes were targeted by qPCR using the High- Resolution Melting method to identify Leishmania parasites. The standard curves were drawn, compared, and identified by high-resolution melting curve analysis.
RESULTS
Melting temperature and Cycle of Threshold of ITS-rDNA was higher than Cyt b but Cyt b was more sensitive than ITS-rDNA when Leishmania major and Leishmania tropica were analyzed and evaluated. By aligning melt curves, normalizing fluorescence curves, and difference plotting melt curves, each Leishmania species was distinguished easily. L. major and L. tropica were separated at 83.6 °C and 84.7 °C, respectively, with less than 0.9 °C of temperature difference. Developing sensitivity and specificity of real-time PCR based on EvaGreen could detect DNA concentration to less than one pmol.
CONCLUSIONS
Precise identification of Leishmania parasites is crucial for strategies of disease control. Real-time PCR using EvaGreen provides rapid, highly sensitive, and specific detection of parasite's DNA. The modified High-Resolution Melting could determine unique curves and was able to detect single nucleotide polymorphisms according to small differences in the nucleotide content of Leishmania parasites.
Topics: Humans; Cytochromes b; DNA, Ribosomal; Leishmaniasis, Cutaneous; Leishmania tropica; Real-Time Polymerase Chain Reaction
PubMed: 36542013
DOI: 10.1590/0037-8682-0186-2022 -
The ISME Journal Oct 2022Methane produced by methanogenic archaea has an important influence on Earth's changing climate. Methanogenic archaea are phylogenetically diverse and widespread in...
Methane produced by methanogenic archaea has an important influence on Earth's changing climate. Methanogenic archaea are phylogenetically diverse and widespread in anoxic environments. These microorganisms can be divided into two subgroups based on whether or not they use b-type cytochromes for energy conservation. Methanogens with b-type cytochromes have a wider substrate range and higher growth yields than those without them. To date, methanogens with b-type cytochromes were found exclusively in the phylum "Ca. Halobacteriota" (formerly part of the phylum Euryarchaeota). Here, we present the discovery of metagenome-assembled genomes harboring methyl-coenzyme M reductase genes reconstructed from mesophilic anoxic sediments, together with the previously reported thermophilic "Ca. Methylarchaeum tengchongensis", representing a novel archaeal order, designated the "Ca. Methylarchaeales", of the phylum Thermoproteota (formerly the TACK superphylum). These microorganisms contain genes required for methyl-reducing methanogenesis and the Wood-Ljundahl pathway. Importantly, the genus "Ca. Methanotowutia" of the "Ca. Methylarchaeales" encode a cytochrome b-containing heterodisulfide reductase (HdrDE) and methanophenazine-reducing hydrogenase complex that have similar gene arrangements to those found in methanogenic Methanosarcinales. Our results indicate that members of the "Ca. Methylarchaeales" are methanogens with cytochromes and can conserve energy via membrane-bound electron transport chains. Phylogenetic and amalgamated likelihood estimation analyses indicate that methanogens with cytochrome b-containing electron transfer complexes likely evolved before diversification of Thermoproteota or "Ca. Halobacteriota" in the early Archean Eon. Surveys of public sequence databases suggest that members of the lineage are globally distributed in anoxic sediments and may be important players in the methane cycle.
Topics: Archaea; Cytochromes; Cytochromes b; Euryarchaeota; Hydrogenase; Methane; Phylogeny
PubMed: 35810262
DOI: 10.1038/s41396-022-01281-0 -
Journal of Genetics 2020Zokor (Myospalacinae) is one of the subterranean rodents, endemic to east Asia. Due to the convergent and parallel evolution induced by its special lifestyles, the...
Zokor (Myospalacinae) is one of the subterranean rodents, endemic to east Asia. Due to the convergent and parallel evolution induced by its special lifestyles, the controversies in morphological classification of zokor appeared at the level of family and genus. To resolve these controversies about taxonomy and phylogeny, the phylogenetic relationships of 20 species of Muroidea and six species of zokors were studied based on complete mitochondrial genome and mitochondrial gene, respectively. Phylogeny analysis of 20 species of Muroidea indicated that the zokor belonged to the family Spalacidae, and it was closer to mole rat rather than bamboo rat. Besides, by investigating the phylogenetic relationships of six species of zokors, the status of two genera of and was affirmed because the two clades differentiated in phylogenetic tree represented two types of zokors, convex occiput type and flat occiput type, respectively. In addition, the two origins in were found diverged at 3.71 million years ago (Ma) based on estimation of divergence time. It is suggested that the climate and ecology changes caused by the Qinghai-Tibet Plateau uplift event in 3.6 Ma led to the inner divergence of . The intraspecific phylogenetic relationships of partial zokors were well resolved, the two clades of represented two geographical populations, respectively, and the divergent pattern of was characterized by allopatric divergence spatially. In this study, we explored the taxonomic status and phylogenetic relationships of Myospalacinae at the molecular level. These works would be significant to understanding the evolutionary process and to clarify the mechanism of differentiation of Myospalacinae.
Topics: Animals; Classification; Cytochromes b; Evolution, Molecular; Genome, Mitochondrial; Mitochondria; Phylogeny; Rodentia; Tibet
PubMed: 32482927
DOI: No ID Found -
Physiologia Plantarum Sep 2017The cytochrome bc (cyt bc) complexes are involved in Q-cycling; they oxidize membrane quinols by high-potential electron acceptors, such as cytochromes or plastocyanin,...
The cytochrome bc (cyt bc) complexes are involved in Q-cycling; they oxidize membrane quinols by high-potential electron acceptors, such as cytochromes or plastocyanin, and generate transmembrane proton gradient. In several prokaryotic lineages, and also in plant chloroplasts, the catalytic core of the cyt bc complexes is built of a four-helical cytochrome b (cyt b) that contains three hemes, a three-helical subunit IV, and an iron-sulfur Rieske protein (cytochrome b f-type complexes). In other prokaryotic lineages, and also in mitochondria, the cyt b subunit is fused with subunit IV, yielding a seven- or eight-helical cyt b with only two hemes (cyt bc -type complexes). Here we present an updated phylogenomic analysis of the cyt b subunits of cyt bc complexes. This analysis provides further support to our earlier suggestion that (1) the ancestral version of cyt bc complex contained a small four-helical cyt b with three hemes similar to the plant cytochrome b and (2) independent fusion events led to the formation of large cyts b in several lineages. In the search for a primordial function for the ancestral cyt bc complex, we address the intimate connection between the cyt bc complexes and photosynthesis. Indeed, the Q-cycle turnover in the cyt bc complexes demands high-potential electron acceptors. Before the Great Oxygenation Event, the biosphere had been highly reduced, so high-potential electron acceptors could only be generated upon light-driven charge separation. It appears that an ancestral cyt bc complex capable of Q-cycling has emerged in conjunction with the (bacterio)chlorophyll-based photosynthetic systems that continuously generated electron vacancies at the oxidized (bacterio)chlorophyll molecules.
Topics: Archaea; Bacteria; Cytochromes b; Cytochromes c; Photosynthesis; Phylogeny
PubMed: 28493482
DOI: 10.1111/ppl.12586 -
Archives of Razi Institute Jul 2021The present study investigated the phylogenetic relationship based on cytochrome b gene sequences among pathogenic Theileria species (spp.) in Iran, including Theileria...
The present study investigated the phylogenetic relationship based on cytochrome b gene sequences among pathogenic Theileria species (spp.) in Iran, including Theileria annulata and Theileria lestoquardi, along with other data available in GenBank. A total of 136 (cattle) and 80 (sheep) blood samples suspected of piroplasm infection were obtained from six different provinces of Iran. Both microscopic and molecular methods using species-specific primers were used for screening T. annulata and T. lestoquardi positive samples. Finally, the partial cytochrome b gene of 30 T. annulata and 5 T .lestoquardi were amplified, sequenced, and deposited in GenBank. The results indicated that there were 12 different genotypes among T. annulata isolates, while only one genotype was observed among T. lestoquardi isolates. T. lestoquardi infection in cattle was detected in one sample, and no T. annulata and T. lestoquardi coinfection were detected in sheep and cattle. In the phylogenetic tree, different Theileria spp. were placed in separate clades, and the reliability of depicted tree and monophyly of T. annulata and T. lestoquardi ingroups were supported by the bootstrap value of 94% which significantly indicated that these two species evolved from a common ancestor. The tree also showed that these two pathogenic spp. shared a more recent common ancestor, compared to another species of Theileria parasites. To the best of our knowledge, this study is the first phylogenic analysis of pathogenic Theileria spp. in Iran based on the cytochrome b gene sequences. In addition, the first T. lestoquardi cytochrome b gene was sequenced and deposited in GenBank.
Topics: Animals; Cattle; Cattle Diseases; Cytochromes b; Iran; Phylogeny; Reproducibility of Results; Sheep; Sheep Diseases; Theileria annulata; Theileriasis
PubMed: 34223723
DOI: 10.22092/ari.2020.341390.1431 -
Biochimica Et Biophysica Acta 2013Most organisms contain a single Rieske/cytb complex. This enzyme can be integrated in any respiratory or photosynthetic electron transfer chain that is quinone-based and... (Review)
Review
Most organisms contain a single Rieske/cytb complex. This enzyme can be integrated in any respiratory or photosynthetic electron transfer chain that is quinone-based and sufficiently energy rich to allow for the turnover of three enzymes - a quinol reductase, a Rieske/cytb complex and a terminal oxidase. Despite this universal usability of the enzyme a variety of phylogenetically distant organisms have multiple copies thereof and no reason for this redundancy is obvious. In this review we present an overview of the distribution of multiple copies among species and describe their properties from the scarce experimental results, analysis of their amino acid sequences and genomic context. We discuss the predicted redox properties of the Rieske cluster in relation to the nature of the pool quinone. It appears that acidophilic iron-oxidizing bacteria specialized one of their two copies for reverse electron transfer, archaeal Thermoprotei adapted their three copies to the interaction with different oxidases and several, phylogenetically unrelated species imported a second complex with a putative heme ci that may confer some yet to be determined properties to the complex. These hypothesis and all the more the so far completely unexplained cases call for further studies and we put forward a number of suggestions for future research that we hope to be stimulating for the field. This article is part of a Special Issue entitled: Respiratory complex III and related bc complexes.
Topics: Archaea; Archaeal Proteins; Bacteria; Bacterial Proteins; Benzoquinones; Cytochromes b; Electron Transport Complex III; Oxidation-Reduction; Phylogeny; Species Specificity
PubMed: 23507620
DOI: 10.1016/j.bbabio.2013.03.003