Animals ; Cell Respiration ; Electron Transport Complex III ; metabolism ; Humans ; Iron-Sulfur Proteins ; chemistry ; metabolism ; Mitochondria ; metabolism ; Peptide Fragments ; chemistry ; metabolism ; Protein Multimerization ; Protein Structure, Quaternary ; Protein Subunits ; chemistry

<p>OBJECTIVETo study the clinical and enzymological characteristics of the children with mitochondrial respiratory chain complex III deficiency.p><p>METHODThe clinical manifestations of five patients (3 males, 2 females) were summarized. Spectrophotometric assay was used for the analysis of respiratory chain complex I to V enzyme activity in peripheral blood leukocytes, after obtaining venous blood.p><p>RESULT(1) Five patients were hospitalized at the age of 1 month to 15 years. Three patients had Leigh syndrome with progressive motor developmental delay or regression and weakness. One had severe liver damage and intrahepatic cholestasis. One presented muscle weakness. (2) Deficient complex I + III activity was identified in five patients. Their complex I + III activities in peripheral blood leukocytes were 3.0 to 14.2 nmol/min per mg mitochondrial protein (control: 84.4 ± 28.5 nmol/min per mg mitochondrial protein). The ratio of complex I + III to citrate synthase decreased to 3.5 to 22.9% (normal control 66.1 ± 14.7%). The activities of complex III decreased to 10.4 to 49.3% of the lowest control value, while complex I, II, IV and V activities were normal. The results supported the diagnosis of isolated respiratory chain complex III deficiency.p><p>CONCLUSIONComplex III deficiency is a kind of disorder of energy metabolism with various manifestations. The complex I + III activities and the ratio of complex I + III to citrate synthase were lower than those of the control. The activities of complex I, II, IV and V were normal.p>
Adolescent ; Child ; Child, Preschool ; Electron Transport Complex I ; metabolism ; Electron Transport Complex II ; metabolism ; Electron Transport Complex III ; metabolism ; Female ; Humans ; Infant ; Leigh Disease ; Leukocytes, Mononuclear ; enzymology ; Male ; Mitochondrial Diseases ; diagnosis ; metabolism ; physiopathology

<p>OBJECTIVETo investigate the mechanisms of Yinxing Pingchan recipe (YXPC) and its components, i.e. the components for detoxicating (A), for calming liver (B) and for dissolving blood stasis(C), in preventing and treating Parkinson's disease, and the path of its inhibition on nigrostriatal dopaminergic neuron (DAn) apoptosis in model mice of Parkinson's disease.p><p>METHODSMale C57BL/6J mice were divided into the normal group, the model group and four Chinese medicinal groups, that is, the YXPC group, and Group A, B and C, treated with YXPC and its components A, B and C respectively. Mouse model of Parkinson's disease was established by intraperitoneal injection with 1-methl-4-phenyl-1,2,3,6-tetrahydropyridin (MPTP). All mice were sacrificed in 2 batches at the 14th and the 28th day respectively. The activity of mitochondrial enzyme complex I, II and IV (MEC I, II and IV) in the brain of mice were measured, respectively.p><p>RESULTSAs compared with the normal group, the activity of MEC I and IV in brain was significantly lower (P < 0.05 or P < 0.01), and that of MEC II had no obvious change in the model group. As compared with the model group, the activity of MEC I was significantly higher in YXPC group and Group C at the 14th day (P < 0.05), while the activity of MECII in Group A at the 14th day, Group B at the 28th day and Group C at both 14th and 28th day was significantly lower (P<0.05 or P<0.01). Activity of MEC IV in the four Chinese medicinal groups at the 14th day all significantly increased (P<0.05 or P<0.01), and retained at high level in Group B and Group C at the 28th day (P<0.05).p><p>CONCLUSIONYXPC and its components can maintain the mitochondrial function by partial inhibiting the activity of its enzyme complex, preventing DAn apoptosis to slow down the progress of Parkinson's disease.p>
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine ; Animals ; Brain ; enzymology ; Drugs, Chinese Herbal ; pharmacology ; Electron Transport Complex I ; metabolism ; Electron Transport Complex II ; metabolism ; Electron Transport Complex III ; metabolism ; Electron Transport Complex IV ; metabolism ; Enzyme Activation ; drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Mitochondria ; enzymology ; Parkinson Disease ; drug therapy ; enzymology ; etiology ; Random Allocation

Intermittent theta burst stimulation (iTBS), a time-saving and cost-effective repetitive transcranial magnetic stimulation regime, has been shown to improve cognition in patients with Alzheimer's disease (AD). However, the specific mechanism underlying iTBS-induced cognitive enhancement remains unknown. Previous studies suggested that mitochondrial functions are modulated by magnetic stimulation. Here, we showed that iTBS upregulates the expression of iron-sulfur cluster assembly 1 (ISCA1, an essential regulatory factor for mitochondrial respiration) in the brain of APP/PS1 mice. In vivo and in vitro studies revealed that iTBS modulates mitochondrial iron-sulfur cluster assembly to facilitate mitochondrial respiration and function, which is required for ISCA1. Moreover, iTBS rescues cognitive decline and attenuates AD-type pathologies in APP/PS1 mice. The present study uncovers a novel mechanism by which iTBS modulates mitochondrial respiration and function via ISCA1-mediated iron-sulfur cluster assembly to alleviate cognitive impairments and pathologies in AD. We provide the mechanistic target of iTBS that warrants its therapeutic potential for AD patients.
Humans ; Mice ; Animals ; Transcranial Magnetic Stimulation ; Alzheimer Disease/therapy* ; Cognitive Dysfunction/therapy* ; Cognition ; Sulfur ; Iron ; Iron-Sulfur Proteins ; Mitochondrial Proteins

Hydrogenases are enzymes that catalyse the oxidation of hydrogen and the reduction of protons. It plays an important role in the process of biohydrogen production. According to the metal atoms within hydrogenase, it can be classified as NiFe-hydrogenase, Fe-hydrogenase and metal-free hydrogenase. The overwhelming majority of hydrogenases are metalloenzymes. The metal atoms are involved in the forming of active site and [Fe-S] clusters. The active site directly catalyzes the reduction of protons and the oxidation of hydrogen. The [Fe-S] clusters are involved in the transport of electrons between the H2-activating site and the redox partners of hydrogenase. Presently, the crystal structures of NiFe-hydrogenase and Fe-hydrogenase from a few kinds of microorganism have been revealed. The metal-free hydrogenase, characterized by the absence of [Fe-S] cluster and the presence of an iron-containing cofactor, shows a great diversity comparing with those of NiFe-hydrogenases and Fe-hydrogenases. Recent progress have also indicated the mechanisms of activation.
Catalysis ; Catalytic Domain ; Hydrogenase ; metabolism ; Iron-Sulfur Proteins ; metabolism ; Oxidation-Reduction

Eukaryotic cells contain numerous iron-requiring proteins such as iron-sulfur (Fe-S) cluster proteins, hemoproteins and ribonucleotide reductases (RNRs). These proteins utilize iron as a cofactor and perform key roles in DNA replication, DNA repair, metabolic catalysis, iron regulation and cell cycle progression. Disruption of iron homeostasis always impairs the functions of these iron-requiring proteins and is genetically associated with diseases characterized by DNA repair defects in mammals. Organisms have evolved multi-layered mechanisms to regulate iron balance to ensure genome stability and cell development. This review briefly provides current perspectives on iron homeostasis in yeast and mammals, and mainly summarizes the most recent understandings on iron-requiring protein functions involved in DNA stability maintenance and cell cycle control.
Animals ; Cell Cycle Checkpoints ; DNA ; metabolism ; DNA Repair ; DNA Replication ; Hemeproteins ; genetics ; metabolism ; Iron ; chemistry ; metabolism ; Iron-Sulfur Proteins ; genetics ; metabolism ; Ribonucleotide Reductases ; genetics ; metabolism ; Yeasts ; metabolism

To enhance biohydrogen production of Klebsiella sp. HQ-3, the global transcriptional factor (Fnr), formate dehydrogenase H (FDH1) and the pncB gene encoding the nicotinic acid phosphoribosyltransferase (NAPRTase) were for the first time over-expressed in Klebsiella sp. HQ-3. The fnr, fdhF, pncB genes were cloned from the genomic DNA of Klebsiella sp. HQ-3 by 3 pairs of universal primers, and introduced into the corresponding sites of the modified pET28a-Pkan, resulting in the plasmids pET28a-Pkan-fnr, pET28a-Pkan-fdhF and pET28a-Pkan-pncB. The 4 plasmids were then electroported into wild Klebsiella sp. HQ-3 to create HQ-3-fnr, HQ-3-fdhF, HQ-3-pncB and HQ-3-C, respectively. Hydrogen production was measured using a gas chromatograph and the metabolites were analyzed with a high-performance liquid chromatograph (HPLC). The results indicate that over-expression of fnr, fdhF and pncB significantly enhanced hydrogen production in the three recombinant strains. Hydrogen production per mol glucose for HQ-3 fnr, HQ-3 pncB, HQ-3 fdhF was 1.113, 1.106 and 1.063 mol of hydrogen/mol glucose, which was respectively increased by 12.26%, 11.62% and 7.28% compared with that of the control strain HQ-3-C (0.991 mol of hydrogen/mol glucose). Moreover, the analysis of HPLC showed that the concentrations of formate and lactate were markedly decreased, but succinate remained unchanged in culture media compared with those of the control strain HQ-3-C.
Fermentation ; Formate Dehydrogenases ; biosynthesis ; genetics ; Hydrogen ; metabolism ; Iron-Sulfur Proteins ; biosynthesis ; genetics ; Klebsiella ; genetics ; metabolism ; Metabolic Engineering ; methods ; Metabolic Networks and Pathways ; Pentosyltransferases ; biosynthesis ; genetics

OBJECTIVE: To clone the full-length gene encoding succinate dehydrogenase iron-sulfur protein of Schistosoma japonicum (SjSDISP) Chinese strain and express it in Escherichia coli. METHODS: According to the published incomplete EST (BU804141) of SjSDISP and the sequence of multiclone sites of lambda gt11 vector, 2 pairs of primers were designed and synthesized. Then the 3' and 5'ends of the EST of the SjSDISP from adult Schistosoma japonicum cDNA library were amplified by anchored PCR. After sequencing, a full-length cDNA sequence of the SjSDISP was obtained, and then it was cloned into prokaryotic expression vector pGEX-4T-1. Identified by agarosed gel electrophoresis, endonucleases digestion and PCR, the resultant recombinant plasmid was used for the expression under the temperature-dependent condition and Western blot analysis. RESULTS: A 1,071 bp sequence was obtained. Sequence analysis showed that the fragment contained a complete open reading frame (ORF), encoding 278 amino acid residues. This target fragment was cloned into the prokaryotic expression vector pGEX-4T-1, and expressed in Escherichia coli. SDS-PAGE revealed that the molecular weight of the expressed fusion recombinant product was 56 kD. Western blot showed that the recombinant protein was recognized by polyclonal rabbit antiserum immunized with Schistosoma japonicum adult worm antigen. CONCLUSION Cloning of the full-length gene encoding SjSDISP and its bacterial expression were successfully done.
Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; Escherichia coli ; metabolism ; Helminth Proteins ; biosynthesis ; genetics ; Iron-Sulfur Proteins ; biosynthesis ; genetics ; Molecular Sequence Data ; Recombinant Proteins ; biosynthesis ; genetics ; Schistosoma japonicum ; genetics ; metabolism ; Sequence Homology ; Succinate Dehydrogenase ; biosynthesis ; genetics

Electron Transport ; Electron Transport Complex III ; deficiency ; Humans ; Mitochondria ; metabolism

DNA primase catalyzes de novo synthesis of a short RNA primer that is further extended by replicative DNA polymerases during initiation of DNA replication. The eukaryotic primase is a heterodimeric enzyme comprising a catalytic subunit Pri1 and a regulatory subunit Pri2. Pri2 is responsible for facilitating optimal RNA primer synthesis by Pri1 and mediating interaction between Pri1 and DNA polymerase α for transition from RNA synthesis to DNA elongation. All eukaryotic Pri2 proteins contain a conserved C-terminal iron-sulfur (Fe-S) cluster-binding domain that is critical for primase catalytic activity in vitro. Here we show that mutations at conserved cysteine ligands for the Pri2 Fe-S cluster markedly decrease the protein stability, thereby causing S phase arrest at the restrictive temperature. Furthermore, Pri2 cysteine mutants are defective in loading of the entire DNA pol α-primase complex onto early replication origins resulting in defective initiation. Importantly, assembly of the Fe-S cluster in Pri2 is impaired not only by mutations at the conserved cysteine ligands but also by increased oxidative stress in the sod1Δ mutant lacking the Cu/Zn superoxide dismutase. Together these findings highlight the critical role of Pri2's Fe-S cluster domain in replication initiation in vivo and suggest a molecular basis for how DNA replication can be influenced by changes in cellular redox state.
Amino Acid Sequence ; Cell Cycle ; Cell Proliferation ; Chromatin Immunoprecipitation ; Cysteine ; genetics ; metabolism ; DNA Primase ; genetics ; metabolism ; DNA Replication ; DNA, Fungal ; genetics ; DNA-Directed DNA Polymerase ; metabolism ; Immunoblotting ; Immunoprecipitation ; Iron ; metabolism ; Iron-Sulfur Proteins ; metabolism ; Molecular Sequence Data ; Mutation ; genetics ; Oxidative Stress ; Protein Binding ; Saccharomyces cerevisiae ; genetics ; growth & development ; metabolism ; Sequence Homology, Amino Acid ; Sulfur ; metabolism