A5017145166- Photosynthetic Processes and Mechanisms
- Metalloenzymes and iron-sulfur proteins
- Algal biology and biofuel production
- Hemoglobin structure and function
- Electrocatalysts for Energy Conversion
- Photoreceptor and optogenetics research
- Marine and coastal ecosystems
- Microbial Fuel Cells and Bioremediation
- Advanced battery technologies research
- Enzyme Catalysis and Immobilization
- Metal-Catalyzed Oxygenation Mechanisms
- Plant responses to water stress
- Electrochemical sensors and biosensors
- Mitochondrial Function and Pathology
- Pancreatic function and diabetes
- Hydrogen Storage and Materials
- Protist diversity and phylogeny
- Plant Stress Responses and Tolerance
- Redox biology and oxidative stress
- Ammonia Synthesis and Nitrogen Reduction
- Asymmetric Hydrogenation and Catalysis
- Cellular transport and secretion
- Nitric Oxide and Endothelin Effects
- Hybrid Renewable Energy Systems
- Epigenetics and DNA Methylation
Ruhr University Bochum
2012-2024
University of California, Los Angeles
2013
University of Bonn
2002-2004
In Chlamydomonas reinhardtii cells, H2 photoproduction can be induced in conditions of sulfur deprivation the presence acetate. The decrease photosystem II (PSII) activity by leads to anoxia, respiration becoming higher than photosynthesis, thereby allowing production. Two different electron transfer pathways, one PSII dependent and other independent, have been proposed account for photoproduction. this study, we investigated contribution both pathways as well acetate requirement production...
Anaerobiosis is a stress condition for aerobic organisms and requires extensive acclimation responses. We used RNA-Seq whole-genome view of the Chlamydomonas reinhardtii to anoxic conditions imposed simultaneously with transfer dark. Nearly 1.4 × 10(3) genes were affected by hypoxia. Comparing transcript profiles from early (hypoxic) those late (anoxic) time points indicated that cells activate oxidative energy generation pathways before employing fermentation. Probable substrates include...
Abstract Background Sealed Chlamydomonas reinhardtii cultures evolve significant amounts of hydrogen gas under conditions sulfur depletion. However, the eukaryotic green alga goes through drastic metabolic changes during this nutritional stress resulting in cell growth inhibition and eventually death. This study aimed at isolating C. transformants which produce normal to allow a continuous metabolism without stressful impact nutrient deprivation. Results To achieve steady photobiological...
Hemoglobins are recognized today as a diverse family of proteins present in all kingdoms life and performing multiple reactions beyond O 2 chemistry. The physiological roles most hemoglobins remain elusive. Here, we show that 2-on-2 (“truncated”) hemoglobin, termed THB8, is required for hypoxic growth the expression anaerobic genes Chlamydomonas reinhardtii . THB8 1 12 this species. It belongs to subclass within hemoglobin class I whose members feature remarkable variety domain arrangements...
The green alga Chlamydomonas reinhardtii has a complex anaerobic metabolism characterized by plastidic hydrogenase (HYD1) coupled to photosynthesis and bacterial-type fermentation system in which pyruvate formate lyase (PFL1) is the central fermentative enzyme. To identify mutant strains with altered hydrogen metabolism, C. nuclear transformant library was screened. Mutant strain 48F5 showed lower light-dependent (H₂) evolution rates reduced vitro activity, H₂ production dark enhanced....
Significance Tuning of the iron-oxygen bonding in hemoproteins is crucial for their versatile O 2 chemistry. The nature Fe-O bond myoglobin (MB) and hemoglobin (HB) has been debated a long time. High-resolution X-ray Kβ emission K-edge absorption spectroscopy on MB HB solutions quantum chemical (time-dependent) density functional theory complete-active-space self-consistent-field calculations revealed an essentially ferrous, intermediate-spin iron ozone-like configuration -bound oxy heme....
The photosynthetic green alga Chlamydomonas reinhardtii is capable of performing a complex fermentative metabolism which related to the mixed acid fermentation bacteria such as Escherichia coli. pattern includes products formate, ethanol, acetate, glycerol, lactate, carbon dioxide and molecular hydrogen (H(2)). H(2) production catalysed by an active [Fe]-hydrogenase (HydA) coupled with electron-transport chain. most important enzyme classic pathway pyruvate formate-lyase, common in but...
We have found the transcript of one at least six ferredoxin encoding genes green alga Chlamydomonas reinhardtii , FDX5 strongly accumulating in anaerobiosis, indicating a vital role encoded protein anaerobic metabolism cells. According to absorption and electron paramagnetic resonance spectroscopy, Fdx5 is plant‐type [2Fe2S]‐ferredoxin with redox potential similar that PetF. However, although seems be located chloroplast, it not able photoreduce nicotinamide adenine dinucleotide phosphate...
The unicellular green alga Chlamydomonas reinhardtii has a special type of anaerobic metabolism that is quite unusual for eukaryotes. It two oxygen-sensitive [Fe-Fe] hydrogenases (EC 1.12.7.2) are coupled to photosynthesis and, in addition, formate- and ethanol-producing fermentative metabolism, which was proposed be initiated by pyruvate formate-lyase (Pfl; EC 2.3.1.54). Pfl enzymes commonly found prokaryotes but only rarely Both the hydrogen- formate/ethanol-producing pathways involved...
Hydrogenases are H2 converting enzymes that harbor catalytic cofactors in which iron (Fe) ions coordinated by biologically unusual carbon monoxide (CO) and cyanide (CN- ) ligands. Extrinsic CO CN- , however, inhibit hydrogenases. The mechanism binds to [FeFe]-hydrogenases is not known. Here, we obtained crystal structures of the -treated [FeFe]-hydrogenase CpI from Clostridium pasteurianum. high resolution 1.39 Å allowed us distinguish intrinsic ligands show extrinsic open coordination site...
The unicellular green alga Chlamydomonas reinhardtii has a complex anaerobic metabolism and reacts to hypoxic or conditions with the induced expression of many genes. One gene which is upregulated particularly strongly FDX5 gene, encoding one at least six ferredoxin isoforms in C. reinhardtii. Fdx5 typical plant-type 2Fe2S protein that located chloroplast. promoter region contains three GTAC motifs, are known be binding sites for copper response regulator 1 (Crr1) other SQUAMOSA proteins...
Abstract The unicellular green alga Chlamydomonas reinhardtii adapts to anaerobic or hypoxic conditions by developing a complex fermentative metabolism including the production of molecular hydrogen [FeFe]-hydrogenase isoform1 (HYDA1). HYDA1 transcript and hydrogenase protein accumulate in absence oxygen copper (Cu). Factors regulating this differential gene expression have been unknown so far. In study, we report on isolation mutant strain impaired screening an insertional mutagenesis...
Molecular hydrogen (H2 ) can be produced in green microalgae by [FeFe]-hydrogenases as a direct product of photosynthesis. The Chlamydomonas reinhardtii hydrogenase HYDA1 contains catalytic site comprising classic [4Fe4S] cluster linked to unique 2Fe sub-cluster. From vitro studies it appears that the is incorporated first housekeeping FeS assembly machinery, followed sub-cluster, whose biosynthesis requires specific maturases HYDEF and HYDG. To investigate maturation process vivo, we...