A5021320642- Metalloenzymes and iron-sulfur proteins
- Microbial Fuel Cells and Bioremediation
- Photosynthetic Processes and Mechanisms
- Methane Hydrates and Related Phenomena
- Porphyrin Metabolism and Disorders
- Electrocatalysts for Energy Conversion
- Metal-Catalyzed Oxygenation Mechanisms
- Anaerobic Digestion and Biogas Production
- Microbial Metabolic Engineering and Bioproduction
- Hydrogen Storage and Materials
- Hybrid Renewable Energy Systems
- ATP Synthase and ATPases Research
- Hemoglobin structure and function
- Mitochondrial Function and Pathology
- Microbial Community Ecology and Physiology
- Catalysis for Biomass Conversion
- Magnetism in coordination complexes
- Bacterial Genetics and Biotechnology
- Organometallic Complex Synthesis and Catalysis
- Advanced Chemical Physics Studies
- Algal biology and biofuel production
Goethe University Frankfurt
2018-2023
Electron bifurcation is a fundamental energy coupling mechanism widespread in microorganisms that thrive under anoxic conditions. These organisms employ hydrogen to reduce CO2, but the molecular mechanisms have remained enigmatic. The key enzyme responsible for powering these thermodynamically challenging reactions electron-bifurcating [FeFe]-hydrogenase HydABC reduces low-potential ferredoxins (Fd) by oxidizing gas (H2). By combining single-particle cryo-electron microscopy (cryoEM)...
Pyruvate:ferredoxin oxidoreductase (PFOR) is a key enzyme in bacterial anaerobic metabolism. Since low-potential ferredoxin (Fd2- ) used as electron carrier, PFOR allows for hydrogen evolution during heterotrophic growth well pyruvate synthesis lithoautotrophic growth. The thermophilic acetogenic model bacterium Thermoanaerobacter kivui can use both modes of lifestyle, but the nature this organism was previously unestablished. Here, we have isolated to apparent homogeneity from cells grown...
Energy-converting hydrogenases (Ech) are ancient, membrane-bound enzymes that use reduced ferredoxin (Fd) as an electron donor to reduce protons molecular H2. Experiments with whole cells, membranes and vesicle-fractions suggest proton reduction is coupled translocation across the cytoplasmatic membrane, but this has never been demonstrated a purified enzyme. To end, we produced His-tagged Ech complex in thermophilic anaerobic bacterium Thermoanaerobacter kivui. The enzyme could be by...
Acetogenic bacteria compete in an energy-limited environment by coupling different metabolic routes to their central metabolism of CO2 fixation. The underlying regulatory mechanisms are often still not understood. In this work, we analysed how lactate is regulated the model acetogen Acetobacterium woodii. Construction a ΔlctCDEF mutant and growth analyses demonstrated that genes essential for on lactate. Subsequent bridging PCR quantitative revealed lctBCDEF form operon was expressed only...
Thermoanaerobacter kivui is an acetogenic model organism that reduces CO2 with electrons derived from H2 or CO, organic substrates in the Wood-Ljugdahl pathway (WLP). For calculation of ATP yields, it necessary to know electron carriers involved coupling oxidative and reductive parts metabolism. Analyses key catabolic oxidoreductases cell-free extract (CFE) purified enzymes revealed physiological involved. The glyceraldehyde-3-phosphate dehydrogenase (GA3P-DH) assayed CFE was NAD+-specific,...
Chemiosmosis and substrate-level phosphorylation are the 2 mechanisms employed to form biological energy currency adenosine triphosphate (ATP). During chemiosmosis, a transmembrane electrochemical ion gradient is harnessed by rotary ATP synthase phosphorylate diphosphate ATP. In microorganisms, this usually composed of H+, but it can also be Na+. Here, we show that strictly anaerobic rumen bacterium Pseudobutyrivibrio ruminis possesses synthases distinct respiratory enzymes, ferredoxin:NAD+...
Lactate oxidation with NAD+ as electron acceptor is a highly endergonic reaction. Some anaerobic bacteria overcome the energetic hurdle by flavin-based bifurcation/confurcation (FBEB/FBEC) using lactate dehydrogenase (Ldh) in concert electron-transferring proteins EtfA and EtfB. The cryo-microscopically characterized (Ldh-EtfAB)2 complex of Acetobacterium woodii at 2.43 Å resolution consists mobile EtfAB shuttle domain located between rigid central Ldh peripheral base units. FADs contact...
Thermoanaerobacter kivui is a thermophilic acetogen that can grow on carbon monoxide as sole and energy source. To identify the gene(s) involved in CO oxidation, genome sequence was analyzed. Two genes potentially encoding dehydrogenases were identified. One, cooS, encodes monofunctional dehydrogenase, whereas another, acsA, CODH component of CODH/ACS complex. Both cloned, His-tag added, proteins produced from plasmid T. kivui. His-AcsA copurified by affinity chromatography with AcsB,...
A major electron carrier involved in energy and carbon metabolism the acetogenic model organism Thermoanaerobacter kivui is ferredoxin, an iron-sulfur-containing, electron-transferring protein. Here, we show that genome of T. encodes four putative ferredoxin-like proteins (TKV_c09620, TKV_c16450, TKV_c10420 TKV_c19530). All genes were cloned, a His-tag encoding sequence was added produced from plasmid kivui. The purified had absorption peak at 430 nm typical for ferredoxins. determined...
Abstract Most of our knowledge on microbial physiology and biochemistry is based studies performed under laboratory conditions. For growing hydrogen-oxidizing anaerobic, autotrophic prokaryotes, an H 2 :CO (80:20, v/v) gas mixture typically used. However, hydrogen concentrations in natural environments are usually low, but may vary a wide range. Here we show that the thermophilic anaerobic bacterium Ammonifex degensii balances its carbon fixation between two pathways depending partial...
Abstract Lactate oxidation with NAD + as electron acceptor is a highly endergonic reaction and some anaerobic bacteria overcome the energetic hurdle by flavin-based bifurcation/confurcation (FBEB/FBEC) using lactate dehydrogenase (Ldh) in concert transferring proteins EtfA EtfB. The cryo-microscopically (cryo-EM) characterized (Ldh-EtfAB) 2 complex of Acetobacterium woodii at 2.43 Å resolution consists mobile EtfAB shuttle located between rigid central Ldh peripheral base units. FADs contact...