A5011455754- Photosynthetic Processes and Mechanisms
- Algal biology and biofuel production
- Mitochondrial Function and Pathology
- Metalloenzymes and iron-sulfur proteins
- Photoreceptor and optogenetics research
- Metal-Catalyzed Oxygenation Mechanisms
- Electrocatalysts for Energy Conversion
- Hemoglobin structure and function
- Microbial Community Ecology and Physiology
- Enzyme Catalysis and Immobilization
- Marine and coastal ecosystems
- Biofuel production and bioconversion
- Advanced biosensing and bioanalysis techniques
- Plant nutrient uptake and metabolism
- Mass Spectrometry Techniques and Applications
- Nanocluster Synthesis and Applications
- Microbial Fuel Cells and Bioremediation
- Biodiesel Production and Applications
- Metabolomics and Mass Spectrometry Studies
- Biocrusts and Microbial Ecology
- Advanced Nanomaterials in Catalysis
- Genomics and Phylogenetic Studies
- Aquatic Ecosystems and Phytoplankton Dynamics
- Electrochemical sensors and biosensors
- bioluminescence and chemiluminescence research
University of Kassel
2021-2025
BioEnergetics (United States)
2024
Kiel University
2019-2023
Accademia Albertina delle Belle Arti
2020
Shanghai Jiao Tong University
2020
University of Insubria
2020
National Renewable Energy Laboratory
2011-2019
Imperial College London
2008-2015
Thomas Young Centre
2014
Czech Academy of Sciences, Institute of Microbiology
2011
We have developed complexes of CdS nanorods capped with 3-mercaptopropionic acid (MPA) and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) that photocatalyze reduction H+ to H2 at a CaI turnover frequency 380–900 s–1 photon conversion efficiencies up 20% under illumination 405 nm. In this paper, we focus on the compositional mechanistic aspects CdS:CaI control photochemical solar energy into H2. Self-assembly was driven by electrostatics, demonstrated as inhibition ferredoxin-mediated...
We report the characterization of biohybrid complexes CdSe quantum dots and ferredoxin NADP+-reductase for photocatalytic regeneration NADPH. Illumination with visible light led to reduction NADP+ NADPH, an apparent kcat 1400 h–1. Regeneration NADPH was coupled aldehydes alcohols catalyzed by a NADPH-dependent alcohol dehydrogenase, each molecule recycled average 7.5 times. The yield both production were 5–6% products. Light-driven also demonstrated in multienzyme system, showing capacity...
Abstract We have investigated the location of Psb27 protein and its role in photosystem (PS) II biogenesis cyanobacterium Synechocystis sp. PCC 6803. Native gel electrophoresis revealed that was present mainly monomeric PSII core complexes but also smaller amounts dimeric complexes, large supercomplexes, unassembled fraction. conclude from analysis assembly mutants isolated histidine-tagged subcomplexes associates with “unassembled” CP43 complex, as well larger containing CP43, possibly...
Biochemical characterization of intermediates involved in the assembly oxygen-evolving Photosystem II (PSII) complex is hampered by their low abundance membrane. Using cyanobacterium Synechocystis sp. PCC 6803, we describe here isolation CP47 and CP43 subunits, which, during biogenesis, attach to a reaction center containing D1, D2, cytochrome b(559), with binding first. Our experimental approach combination His tagging, use D1 deletion mutant that blocks PSII at an early stage, and, case...
The decarboxylation of pyruvate is a central reaction in the carbon metabolism all organisms. It catalyzed by pyruvate:ferredoxin oxidoreductase (PFOR) and dehydrogenase (PDH) complex. Whereas PFOR reduces ferredoxin, PDH complex utilizes NAD+. Anaerobes rely on PFOR, which was replaced during evolution found aerobes. Cyanobacteria possess both enzyme systems. Our data challenge view that exclusively utilized for fermentation. Instead, we show, cyanobacterial stable presence oxygen vitro...
Photosystem II (PSII) mutants are useful experimental tools to trap potential intermediates involved in the assembly of oxygen-evolving PSII complex. Here, we focus on subunit composition RC47 complex that accumulates a psbC null mutant cyanobacterium Synechocystis sp. PCC 6803 unable make CP43 apopolypeptide. By using native gel electrophoresis, showed is heterogeneous and mainly found as monomer 220 kDa. complexes co-purify with small Cab-like proteins (ScpC and/or ScpD) Psb28 its...
Abstract FtsH metalloproteases are key components of the photosystem II (PSII) repair cycle, which operates to maintain photosynthetic activity in light. Despite their physiological importance, structure and subunit composition thylakoid complexes remain uncertain. Mutagenesis has previously revealed that four homologs encoded by cyanobacterium Synechocystis sp PCC 6803 functionally different: FtsH1 FtsH3 required for cell viability, whereas FtsH2 FtsH4 dispensable. To gain insights into...
Significance Our results suggest that particular ferredoxins in photosynthetic organisms are tailored to serve as electron carriers sustain day-time and night-time metabolism the chloroplast-localized ferredoxin-5 (FDX5) appears function desaturation of fatty acids required for maintaining correct ratio dominant lipids thylakoid membranes integration chloroplast mitochondrial metabolism, which is absolutely growth dark. The most important messages from this work redox components associated...
The cyanobacterium Synechocystis sp. PCC 6803 expresses four different FtsH protease subunits (FtsH1-4) that assemble into specific homo- and heterocomplexes. FtsH2/FtsH3 complex is involved in photoprotection but the physiological roles of other complexes, notably essential FtsH1/FtsH3 complex, remain unclear. Here we show FtsH1 FtsH3 proteases are acclimation cells to iron deficiency. A mutant conditionally depleted was unable induce normal expression IsiA chlorophyll-protein FutA1...
Cyanobacteria switch their carbon metabolism between photoautotrophy and heterotrophy during diurnal cycles. In cyanobacteria, the classical glycolytic control point is characterized by two catabolic phosphofructokinases (PFKs) a bifunctional anabolic fructose-1,6-biphosphatase/sedoheptulose-1,7-biphosphatase (F/SBPase; slr2094) catalyzing key reactions in Calvin-Benson-Bassham (CBB) cycle. addition, Synechocystis possesses fructose-1,6-bisphosphatase (FBPase; slr0952) with yet unknown...
Flavodiiron proteins (FDPs) catalyse light-dependent reduction of oxygen to water in photosynthetic organisms, creating an electron sink on the acceptor side Photosystem I that protects apparatus. However, ambiguity about donor(s) remains, and molecular mechanisms regulating FDP activity have remained elusive. We employed spectroscopic gas flux analysis transport, bimolecular fluorescence complementation assays for vivo protein-protein interactions model cyanobacterium Synechocystis sp. PCC...
Band 7 proteins, which encompass members of the stomatin, prohibitin, flotillin, and HflK/C protein families, are integral membrane proteins that play important physiological roles in eukaryotes but poorly characterized bacteria. We have studied band encoded by cyanobacterium Synechocystis sp. strain PCC 6803, with emphasis on their structure proposed role assembly maintenance photosynthetic apparatus. Mutagenesis revealed none five (Slr1106, Slr1128, Slr1768, Sll0815, Sll1021) was essential...
We present here the crystal structure of CyanoP (Tlr2075) from Thermosynechococcus elongatus at 2.8 A. is a substoichiometric component isolated cyanobacterial Photosystem II (PSII) complex, distantly related to PsbP extrinsic subunit oxygen-evolving PSII complex in higher plants and green algae. Despite relatively low degree sequence similarity, we have found that adopts same beta-sandwich fold as higher-plant contains well-conserved metal (zinc)-binding site also plant PsbP. Our results...
Hydrogenases are metalloenzymes that catalyze 2H(+) + 2e(-) ↔ H(2). A multisubunit, bidirectional [NiFe]-hydrogenase has been identified and characterized in a number of bacteria, including cyanobacteria, where it is hypothesized to function as an electron valve, balancing reductant the cell. In this Hox hydrogenase consists five proteins two functional moieties: moiety (HoxYH) with homology heterodimeric [NiFe]-hydrogenases diaphorase (HoxEFU) NuoEFG respiratory Complex I, linking NAD(P)H...
The PsbQ-like protein, termed CyanoQ, found in the cyanobacterium Synechocystis sp. PCC 6803 is thought to bind lumenal surface of photosystem II (PSII), helping shield Mn4CaO5 oxygen-evolving cluster. CyanoQ is, however, absent from crystal structures PSII isolated thermophilic cyanobacteria raising possibility that association with might not be a conserved feature. Here, we show (encoded by tll2057) indeed expressed Thermosynechococcus elongatus and provide evidence support its assignment...
Cyanobacterial Hox is a [NiFe] hydrogenase that consists of the hydrogen (H2)-activating subunits HoxYH, which form complex with HoxEFU assembly to mediate reactions soluble electron carriers like NAD(P)H and ferredoxin (Fdx), thereby coupling photosynthetic transfer energy-transforming catalytic reactions. Researchers studying HoxEFUYH have observed can be isolated independently leading hypothesis distinct functional subcomplex rather than an artifact isolation. Moreover, outstanding...
The green alga Chlamydomonas reinhardtii contains six plastidic [2Fe2S]-cluster ferredoxins (FDXs), with FDX1 as the predominant isoform under photoautotrophic growth. FDX2 is highly similar to and has been shown interact specific enzymes (such nitrite reductase), well share interactors FDX1, such hydrogenases (HYDA), ferredoxin:NAD(P) reductase I (FNR1), pyruvate:ferredoxin oxidoreductase (PFR1), albeit performing at low catalytic rates. Here we report crystal structure solved 1.18 Å...
The cyanobacterium Synechocystis sp.PCC 6803 possesses a bidirectional NiFe-hydrogenase, HoxEFUYH. It functions to produce hydrogen under dark, fermentative conditions and photoproduces when dark-adapted cells are illuminated. Unexpectedly, we found that the deletion of large subunit hydrogenase (HoxH) in leads an inability grow on arginine glucose continuous light presence oxygen. This is surprising, as oxygen-sensitive enzyme. In wild-type (WT) cells, thylakoid membranes largely...