A5054043035- Microbial Community Ecology and Physiology
- Metalloenzymes and iron-sulfur proteins
- Genomics and Phylogenetic Studies
- Metal Extraction and Bioleaching
- Nitrogen and Sulfur Effects on Brassica
- Cassava research and cyanide
- Enzyme Structure and Function
- Photosynthetic Processes and Mechanisms
- Microbial Fuel Cells and Bioremediation
- Arsenic contamination and mitigation
- Mine drainage and remediation techniques
- Anaerobic Digestion and Biogas Production
- Chromium effects and bioremediation
- Sulfur Compounds in Biology
- Radioactive element chemistry and processing
- Nuclear physics research studies
- Porphyrin Metabolism and Disorders
- Microbial metabolism and enzyme function
- Methane Hydrates and Related Phenomena
- Quantum Chromodynamics and Particle Interactions
- Trace Elements in Health
- Particle physics theoretical and experimental studies
- Biochemical Acid Research Studies
- X-ray Spectroscopy and Fluorescence Analysis
- Enzyme function and inhibition
University of Bonn
2015-2024
Institut für Medizinische Biometrie, Informatik und Epidemiologie
1997-2011
Pacific Northwest National Laboratory
2010
GTx (United States)
1998
Harvard University
1987
Sulfate reduction via a trisulfide Microorganisms can respire sulfur compounds in the absence of oxygen, eventually leading to production hydrogen sulfide. This ancient metabolism is common modern anoxic environments, but enzymatic pathways aren't yet fully resolved. Through vivo and vitro experiments, Santos et al. clarify enzymology sulfate pathway both bacteria archaea (see Perspective by Fritz Kroneck). Reduction sulfite intermediate results linkage two cysteine residues third atom from...
Seven new genes designated dsrLJOPNSR were identified immediately downstream of dsrABEFHCMK, completing the dsr gene cluster phototrophic sulfur bacterium Allochromatium vinosum D (DSM 180(T)). Interposon mutagenesis proved an essential role encoded proteins for oxidation intracellular sulfur, obligate intermediate during sulfide and thiosulfate. While dsrR dsrS encode cytoplasmic unknown function, other a predicted NADPH:acceptor oxidoreductase (DsrL), triheme c-type cytochrome (DsrJ),...
The sequence of the dsr gene region phototrophic sulfur bacterium Chromatium vinosum D (DSMZ 180 T ) was determined to clarify in vivo role ‘reverse’ sirohaem sulfite reductase. dsrAB genes encoding dissimilatory reductase are part a cluster, dsrABEFHCMK, that encodes four small, soluble proteins (DsrE, DsrF, DsrH and DsrC), transmembrane protein (DsrM) with similarity haem-b-binding polypeptides (DsrK) resembling [4Fe---4S]-cluster-containing heterodisulfide from methanogenic archaea....
Summary Two different pathways for thiosulphate oxidation are present in the purple sulphur bacterium Allochromatium vinosum : to tetrathionate and complete sulphate with obligatory formation of globules as intermediates. The tetrathionate:sulphate ratio is strongly pH‐dependent being preferred under acidic conditions. Thiosulphate dehydrogenase, a constitutively expressed monomeric 30 kDa c ‐type cytochrome pH optimum at 4.2 catalyses formation. A periplasmic thiosulphate‐oxidizing...
Sulfur-oxidizing prokaryotes (SOP) catalyse a central step in the global S-cycle and are of major functional importance for variety natural engineered systems, but our knowledge on their actual diversity environmental distribution patterns is still rather limited. In this study we developed specific PCR assay detection dsrAB that encode reversely operating sirohaem dissimilatory sulfite reductase (rDSR) present many not all published genomes SOP. The was used to screen 42 strains SOP (most...
In phototrophic sulfur bacteria, sulfite is a well-established intermediate during reduced compound oxidation. Sulfite generated in the cytoplasm by reverse-acting dissimilatory reductase DsrAB. Many purple bacteria can even use externally available as photosynthetic electron donor. Nevertheless, exact mode of oxidation these organisms long-standing enigma. Indirect via adenosine-5'-phosphosulfate (APS) catalysed APS and ATP sulfurylase neither generally present nor essential. The inhibition...
Natural and anthropogenic wetlands are major sources of the atmospheric greenhouse gas methane. Methane emissions from mitigated by methanotrophic bacteria at oxic–anoxic interface, a zone intense redox cycling carbon, sulfur, nitrogen compounds. Here, we report on isolation an aerobic bacterium, ‘ Methylovirgula thiovorans ' strain HY1, which possesses metabolic capabilities never before found in any methanotroph. Most notably, HY1 is first bacterium shown to aerobically oxidize both...
X-ray absorption near edge structure (XANES) spectroscopy at the sulfur K-edge was applied to probe speciation of metabolically different sulfur-accumulating bacteria in situ. Fitting spectra using a least-square fitting routine XANES reveals least three forms bacterial globules. Cyclooctasulfur dominates globules Beggiatoa alba and very recently described giant bacterium Thiomargarita namibiensis. A second type is present Acidithiobacillus ferrooxidans: here occurs as polythionates. In...
Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step reduced compounds is catalyzed by sulfite:cytochrome c oxidoreductase (EC ). Here we show that enzyme from Thiobacillus novellus a periplasmically located alphabeta heterodimer, consisting 40.6-kDa subunit containing molybdenum cofactor an 8.8-kDa mono-heme cytochrome c(552) (midpoint redox potential, E(m8.0) = +280 mV). The organic component was identified...
Summary: The genes for adenosine-5′-phosphosulfate (APS) reductase, aprBA , and sirohaem sulfite dsrAB from the sulfur-oxidizing phototrophic bacterium Chromatium vinosum strain D (DSMZ 180 T ) were cloned sequenced. Statistically significant sequence similarities similar physicochemical properties suggest that gene products Chr . are true homologues of their counterparts sulfate-reducing chemotrophic archaeon Archaeoglobus fulgidus Desulfovibrio vulgaris Evidence proposed duplication a...
The effects of ergosterol, yeast's natural sterol, on cell cycling and a protein kinase antigenically related to pp60v-src were examined in sterol auxotroph Saccharomyces cerevisiae. Sterol-depleted cells accumulate an unbudded, G1 state. Cell budding proliferation are reinitiated upon addition nonlimiting ergosterol or cholesterol with trace whereas alone is less effective. Stimulation associated immune complexes yeast anti-pp60v-src shows positive correlation exit from the phase following...
SUMMARY: A dissimilatory sulphite reductase was isolated from the extremely thermophilic sulphate-reducing archaeon Archaeoglobus fulgidus. In common with other reductases thus far characterized, enzyme has an α2β2-structure and contains sirohaem, non-haem iron atoms acid labile sulphide. The oxidized exhibited absorption maxima at 281, 394, 545 593 nm a weak band around 715 nm. We have cloned sequenced genes for α β subunits of this enzyme, which we designate dsrA dsrB, respectively. They...
Summary In this work we identified the gene for tetrathionate‐forming thiosulfate dehydrogenase (TsdA) from purple sulfur bacterium Allochromatium vinosum by sequence analysis and reverse genetics. The recombinant protein produced in Escherichia coli is a periplasmic, monomeric 25.8 kDa dihaem cytochrome c with an enzyme activity optimum at pH 4. UV‐visible electron paramagnetic resonance spectroscopy indicate methionine (strictly conserved M 222 or 236 ) cysteine (C 123 as probable sixth...
Iron-sulfur clusters serve as indispensable cofactors within proteins across all three domains of life. Fe/S emerged early during the evolution life on our planet and biogeochemical cycle sulfur is one most ancient important element cycles. It therefore no surprise that have crucial roles in multiple steps microbial metabolism. During dissimilatory oxidation prokaryotes, not only electron carriers several steps, but also perform catalytic roles, including unprecedented reactions. Two...
Allochromatium vinosum formerly Chromatium is a mesophilic purple sulfur bacterium belonging to the family Chromatiaceae in bacterial class Gammaproteobacteria. The genus contains currently five species. All members were isolated from freshwater, brackish water or marine habitats and are predominately obligate phototrophs. Here we describe features of organism, together with complete genome sequence annotation. This first completed member within bacteria thriving globally occurring habitats....
While the importance of sulfur transfer reactions is well established for a number biosynthetic pathways, evidence has only started to emerge that sulfurtransferases may also be major players in sulfur-based microbial energy metabolism. Among first organisms studied this regard phototrophic purple bacterium Allochromatium vinosum. During oxidation reduced species sulfate Gammaproteobacterium accumulates globules. Low molecular weight organic persulfides have been proposed as carrier...