U. Kappler

Direct catalytic electrochemistry of sulfite dehydrogenase: Mechanistic insights and contrasts with related Mo enzymes (2008)

Rapson, T., Kappler, U., Bernhardt, P.V.

Bacterial Sulfite-Oxidizing Enzymes - enzymes for Chemolithotrophs Only? (2008)

Kappler, U.

In nature, sulfur occurs in many different oxidation states and is one of the most versatile elements in life. It is an integral part of many important cell constituents, such as the amino acids...

Molecular basis for enzymatic sulfite oxidation: How three conserved active site residues shape enzyme activity (2008)

Bailey, S., Rapson, T., Johnson-Winters, K., Atashkin, A.V., Enemark, J.H., Kappler, U.

SoxAX cytochromes, a new type of heme copper protein involved in bacterial energy generation from sulfur compounds (2008)

Kappler, U., Bernhardt, P.V., Kilmartin, J., Riley, M.J., Teschner, J., McKenzie, K.J., ...

Using anoxygenic photosynthetic bacteria for the removal of sulfide from wastewater (2008)

Hurse, T. J., Kappler, U., Keller, J.

Bacterial sulfite-oxidizing enzymes - insights into the molecular and structural basis of enzymatic sulfite oxidation (2008)

Bailey, S., Kappler, U.

PrrC, a Sco homologue from Rhodobacter sphaeroides, possesses thiol-disulfide oxidoreductase activity (2007)

Badrick, A. C., Hamilton, A. J., Bernhardt, P. V., Jones, C. E., Kappler, U., Jennings, M. P., ...

PrrC is a Sco homologue in Rhodobacter sphaeroides that is associated with PrrBA, a two-component signal transduction system that induces photosynthesis gene expression in response to a decrease in...

The NT-26 cytochrome c552 and its role in arsenite oxidation (2007)

Santini, J. M., Kappler, U., Ward, S. A., Honeychurch, M. J., Vanden Hoven, R. N., Bernhardt, P. V.

Arsenite oxidation by the facultative chemolithoautotroph NT-26 involves a periplasmic arsenite oxidase. This enzyme is the first component of an electron transport chain which leads to reduction of...

Visualisation of pyrite leaching by selected thermophilic archaea: nature of microorganism-ore interactions during bioleaching (2007)

Mikkelsen, D., Kappler, U., Webb, R. I., Rasch, R., McEwan, A. G., Sly, L. I.

In this study, pyrite (FeS2) was leached by Acidianus brierleyi, Metallosphaera sedula and Sulfolobus metallicus during a 60 day experimental period. Leaching occurred over a redox potential range of...

PrrC, a Sco homologue from Rhodobacter sphaeroides, possesses thiol-disulfide oxidoreductase activity (2007)

Badrick, A. C., Hamilton, A. J., Bernhardt, P. V., Jones, C. E., Kappler, U., Jennings, M. P., ...

PrrC is a Sco homologue in Rhodobacter sphaeroides that is associated with PrrBA, a two-component signal transduction system that induces photosynthesis gene expression in response to a decrease in...

The NT-26 cytochrome c552 and its role in arsenite oxidation (2007)

Santini, J. M., Kappler, U., Ward, S. A., Honeychurch, M. J., Vanden Hoven, R. N., Bernhardt, P. V.

Arsenite oxidation by the facultative chemolithoautotroph NT-26 involves a periplasmic arsenite oxidase. This enzyme is the first component of an electron transport chain which leads to reduction of...

Visualisation of pyrite leaching by selected thermophilic archaea: nature of microorganism-ore interactions during bioleaching (2007)

Mikkelsen, D., Kappler, U., Webb, R. I., Rasch, R., McEwan, A. G., Sly, L. I.

In this study, pyrite (FeS2) was leached by Acidianus brierleyi, Metallosphaera sedula and Sulfolobus metallicus during a 60 day experimental period. Leaching occurred over a redox potential range of...

Pulsed EPR investigations of the molybdenum centers of sulfite oxidizing enzymes and related model compounds (2006)

Enemark, JH, Astashkin, AV, Feng, CJ, Kappler, U, Raitsimring, AM, Neese, F, ...

Lasers - An effective artificial source of radiation for the cultivation of anoxygenic photosynthetic bacteria (2006)

Bertling, K., Hurse, T. J., Kappler, U., Rakic, A. D.

The laser diode (LD) is a unique light source that can efficiently produce all radiant energy within the narrow wavelength range used most effectively by a photosynthetic microorganism. We have...

Kinetic and structural evidence for the importance of Tyr236 for the integrity of the Mo active site in a bacterial sulfite dehydrogenase (2006)

Kappler, U., Bailey, S., Feng, C., Honeychurch, M. J., Hanson, G. R., Bernhardt, P. V., ...

The sulfite dehydrogenase from Starkeya novella is the only known sulfite-oxidizing enzyme that forms a permanent heterodimeric complex between a molybdenum and a heme c-containing subunit and can be...

Structure of the active site of sulfite dehydrogenase from Starkeya novella (2006)

Doonan, C. J., Kappler, U., George, G. N.

In this paper, we report the results of molybdenum K-edge X-ray absorption studies performed on the oxidized and reduced active sites of the sulfite dehydrogenase from Starkeya novella. Our results...

Pulsed EPR investigations of the molybdenum centers of sulfite oxidizing enzymes and related model compounds (2006)

Enemark, JH, Astashkin, AV, Feng, CJ, Kappler, U, Raitsimring, AM, Neese, F, ...

Kinetic and structural evidence for the importance of Tyr236 for the integrity of the Mo active site in a bacterial sulfite dehydrogenase (2006)

Kappler, U., Bailey, S., Feng, C., Honeychurch, M. J., Hanson, G. R., Bernhardt, P. V., ...

The sulfite dehydrogenase from Starkeya novella is the only known sulfite-oxidizing enzyme that forms a permanent heterodimeric complex between a molybdenum and a heme c-containing subunit and can be...

Lasers - An effective artificial source of radiation for the cultivation of anoxygenic photosynthetic bacteria (2006)

Bertling, K., Hurse, T. J., Kappler, U., Rakic, A. D.

The laser diode (LD) is a unique light source that can efficiently produce all radiant energy within the narrow wavelength range used most effectively by a photosynthetic microorganism. We have...

Structure of the active site of sulfite dehydrogenase from Starkeya novella (2006)

Doonan, C. J., Kappler, U., George, G. N.

In this paper, we report the results of molybdenum K-edge X-ray absorption studies performed on the oxidized and reduced active sites of the sulfite dehydrogenase from Starkeya novella. Our results...

Respiratory gene clusters of Metallosphaera sedula - differential expression and transcriptional organization (2005)

Kappler, U., Sly, L. I., McEwan, A. G.

Metallosphaera sedula is a thermoacidophilic Crenarchaeon which is capable of leaching metals from sulfidic ores. The authors have investigated the presence and expression of genes encoding...

Pulsed EPR studies of a bacterial sulfite-oxidizing enzyme with pH-invariant hyperfine interactions from exchangeable protons (2005)

Raitsimring, A. M.., Kappler, U., Feng, C. J., Astashkin, A. V., Enemark, J. H.

Variable-frequency pulsed electron paramagnetic resonance studies of the molybdenum(V) center of sulfite dehydrogenase (SDH) clearly show couplings from nearby exchangeable protons that are assigned...

Structural and kinetic properties of a wild-type bacterial sulfite dehydrogenase and a Y236F active site mutant of this enzyme (2005)

Kappler, U., Bailey, S.

Molecular mechanism of intramolecular electron transfer in sulfite-oxidizing enzymes us revealed by the high resolution structure of a heterodimeric bacterial sulfite dehydrogenase (2005)

Kappler, U., Bailey, S.

A recombinant diheme SoxAX cytochrome - implications for the relationship between EPR signals and modified heme-ligands (2005)

Kappler, U., Hanson, G. R., Jones, A.

Microbial dimethylsulfoxide and trimethylamine-N-oxide respiration (2005)

McCrindle, S. L., Kappler, U., McEwan, A. G.

Over the last two decades, the biochemistry and genetics of dimethylsulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) respiration has been characterised, particularly in Escherichia coli, marine...

Microbial dimethylsulfoxide and trimethylamine-N-oxide respiration (2005)

McCrindle, S. L., Kappler, U., McEwan, A. G.

Over the last two decades, the biochemistry and genetics of dimethylsulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) respiration has been characterised, particularly in Escherichia coli, marine...

Molecular basis of intramolecular electron transfer in sulfite-oxidizing enzymes is revealed by high resolution structure of a heterodimeric complex of the catalytic molybdopterin subunit and a c-type cytochrome subunit (2005)

Kappler, U., Bailey, S.

Sulfite-oxidizing molybdoenzymes convert the highly reactive and therefore toxic sulfite to sulfate and have been identified in insects, animals, plants, and bacteria. Although the well studied...

A recombinant diheme SoxAX cytochrome - implications for the relationship between EPR signals and modified heme-ligands (2005)

Kappler, U., Hanson, G. R., Jones, A

Microbial dimethylsulfoxide and trimethylamine-N-oxide respiration (2005)

McCrindle, S. L., Kappler, U., McEwan, A. G.

Over the last two decades, the biochemistry and genetics of dimethylsulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) respiration has been characterised, particularly in Escherichia coli, marine...

Molecular basis of intramolecular electron transfer in sulfite-oxidizing enzymes is revealed by high resolution structure of a heterodimeric complex of the catalytic molybdopterin subunit and a c-type cytochrome subunit (2005)

Kappler, U., Bailey, S.

Sulfite-oxidizing molybdoenzymes convert the highly reactive and therefore toxic sulfite to sulfate and have been identified in insects, animals, plants, and bacteria. Although the well studied...

Respiratory gene clusters of Metallosphaera sedula - differential expression and transcriptional organization (2005)

Kappler, U., Sly, L. I., McEwan, A. G.

Metallosphaera sedula is a thermoacidophilic Crenarchaeon which is capable of leaching metals from sulfidic ores. The authors have investigated the presence and expression of genes encoding...

Pulsed EPR studies of a bacterial sulfite-oxidizing enzyme with pH-invariant hyperfine interactions from exchangeable protons (2005)

Raitsimring, A. M.., Kappler, U., Feng, C. J., Astashkin, A. V., Enemark, J. H.

Variable-frequency pulsed electron paramagnetic resonance studies of the molybdenum(V) center of sulfite dehydrogenase (SDH) clearly show couplings from nearby exchangeable protons that are assigned...

Structural and kinetic properties of a wild-type bacterial sulfite dehydrogenase and a Y236F active site mutant of this enzyme (2005)

Kappler, U., Bailey, S.

Molecular mechanism of intramolecular electron transfer in sulfite-oxidizing enzymes us revealed by the high resolution structure of a heterodimeric bacterial sulfite dehydrogenase (2005)

Kappler, U., Bailey, S.

A recombinant diheme SoxAX cytochrome - implications for the relationship between EPR signals and modified heme-ligands (2005)

Kappler, U., Hanson, G. R., Jones, A.

Microbial dimethylsulfoxide and trimethylamine-N-oxide respiration (2005)

McCrindle, S. L., Kappler, U., McEwan, A. G.

Over the last two decades, the biochemistry and genetics of dimethylsulfoxide (DMSO) and trimethylamine-N-oxide (TMAO) respiration has been characterised, particularly in Escherichia coli, marine...

Microbial molybdenum-containing enzymes in respiration: Structural and functional aspects (2004)

McEwan, A. G., Kappler, U., Mc Devitt, C.

Crystallization and preliminary X-ray analysis of sulfite dehydrogenase from Stargeya novella (2004)

Kappler, U., Bailey, S.

Crystals of purified heterodimeric sulfite dehydrogenase from Starkeya novella have been grown using vapour diffusion. X-ray diffraction data have been collected from crystals of the native protein...

Respiratory gene clusters of Metallosphaera sedula (2004)

Kappler, U., Sly, L. I., McEwan, A. G.

Cytochrome c551 from Starkeya novella - characterization, spectroscopic properties and phylogeny of a diheme protein of the SoxAX family (2004)

Kappler, U., Aguey, F.K., Hanson, G. R., Bernhardt, P. V., McEwan, A. G.

Cytochrome c(551) from Starkeya novella - Characterization, spectroscopic properties, and phylogeny of a diheme protein of the SoxAX family (2004)

Kappler, U., Aguey, F. K., Hanson, G. R., Bernhardt, P. V., McEwan, A. G.

Cytochromes from the SoxAX family have a major role in thiosulfate oxidation via the thiosulfate-oxidizing multi-enzyme system (TOMES). Previously characterized SoxAX proteins from Rhodovulum...

Microbial molybdenum-containing enzymes in respiration: Structural and functional aspects (2004)

McEwan, A. G., Kappler, U., Mc Devitt, C.

Cytochrome c(551) from Starkeya novella - Characterization, spectroscopic properties, and phylogeny of a diheme protein of the SoxAX family (2004)

Kappler, U., Aguey, F. K., Hanson, G. R., Bernhardt, P. V., McEwan, A. G.

Cytochromes from the SoxAX family have a major role in thiosulfate oxidation via the thiosulfate-oxidizing multi-enzyme system (TOMES). Previously characterized SoxAX proteins from Rhodovulum...

Crystallization and preliminary X-ray analysis of sulfite dehydrogenase from Stargeya novella (2004)

Kappler, U., Bailey, S.

Crystals of purified heterodimeric sulfite dehydrogenase from Starkeya novella have been grown using vapour diffusion. X-ray diffraction data have been collected from crystals of the native protein...

Respiratory gene clusters of Metallosphaera sedula (2004)

Kappler, U., Sly, L. I., McEwan, A. G.

Cytochrome c551 from Starkeya novella - characterization, spectroscopic properties and phylogeny of a diheme protein of the SoxAX family (2004)

Kappler, U., Aguey, F.K., Hanson, G. R., Bernhardt, P. V., McEwan, A. G.

Bacterial sulfite oxidase (2003)

Kappler, U.

The Rhodobacter capsulatus dor promoter: A useful tool for the heterologous expression of redox proteins (2003)

Kappler, U., McEwan, A. G.

Probing molecular properties: Direct electrochemistry of sulfite dehydrogenase from Starkeya novella (2003)

Aguey, F.K., Bernhardt, P. V., Kappler, U., McEwan, A. G.

Direct electrochemistry of a bacterial sulfite dehydrogenase (2003)

Aguey-Zinsou, K. F., Bernhardt, P. V., Kappler, U., McEwan, A. G.

Sulfite dehydrogenase from Starkeya novella is an alphabeta heterodimer comprising a 40.6 kDa subunit (containing the Mo cofactor) and a smaller 8.8 kDa heme c subunit. The enzyme catalyses the...

Direct electrochemistry of a bacterial sulfite dehydrogenase (2003)

Aguey-Zinsou, K. F., Bernhardt, P. V., Kappler, U., McEwan, A. G.

Sulfite dehydrogenase from Starkeya novella is an alphabeta heterodimer comprising a 40.6 kDa subunit (containing the Mo cofactor) and a smaller 8.8 kDa heme c subunit. The enzyme catalyses the...

Bacterial sulfite oxidase (2003)

Kappler, U.

The Rhodobacter capsulatus dor promoter: A useful tool for the heterologous expression of redox proteins (2003)

Kappler, U., McEwan, A. G.

Probing molecular properties: Direct electrochemistry of sulfite dehydrogenase from Starkeya novella (2003)

Aguey, F.K., Bernhardt, P. V., Kappler, U., McEwan, A. G.

A system for the heterologous expression of complex redox proteins in Rhodobacter capsulatus: characterisation of recombinant sulphite : cytochrome c oxidoreductase from Starkeya novella (2002)

Kappler, U., McEwan, A. G.

The phototrophic purple non-sulfur bacterium Rhodobacter capsulatus expresses a wide variety of complex redox proteins in response to changing environmental conditions. Here we report the...

Control of dimethylsulfoxide reductase expression in Rhodobacter capsulatus: the role of carbon metabolites and the response regulators DorR and RegA (2002)

Kappler, U., Huston, W. M., McEwan, A. G.

Regulation of the expression of dimethylsulfoxide (DMSO) reductase was investigated in the purple phototrophic bacterium Rhodobacter capsulatus. Under phototrophic, anaerobic conditions with malate...

A system for the heterologous expression of complex redox proteins in Rhodobacter capsulatus: characterisation of recombinant sulphite : cytochrome c oxidoreductase from Starkeya novella (2002)

Kappler, U., McEwan, A. G.

The phototrophic purple non-sulfur bacterium Rhodobacter capsulatus expresses a wide variety of complex redox proteins in response to changing environmental conditions. Here we report the...

Control of dimethylsulfoxide reductase expression in Rhodobacter capsulatus: the role of carbon metabolites and the response regulators DorR and RegA (2002)

Kappler, U., Huston, W. M., McEwan, A. G.

Regulation of the expression of dimethylsulfoxide (DMSO) reductase was investigated in the purple phototrophic bacterium Rhodobacter capsulatus. Under phototrophic, anaerobic conditions with malate...

Evidence for two pathways of thiosulfate oxidation in Starkeya novella (formerly Thiobacillus novellus) (2001)

Kappler, U., Friedrich, C. G., Truper, H. G., Dahl, C.

The pathway of thiosulfate oxidation in the facultatively chemolithotrophic, sulfur-oxidizing bacterium Starkeya novella (formerly Thiobacillus novellus) has not been established beyond doubt....

Dissimilatory ATP sulfurylase from Archaeoglobus fulgidus (2001)

Sperling, D., Kappler, U., Truper, H. G., Dahl, C.

Enzymology and molecular biology of prokaryotic sulfite oxidation (2001)

Kappler, U., Dahl, C.

Despite its toxicity, sulfite plays a key role in oxidative sulfur metabolism and there are even some microorganisms which can use it as sole electron source. Sulfite is the main intermediate in the...

Dissimilatory ATP sulfurylase from Archaeoglobus fulgidus (2001)

Sperling, D., Kappler, U., Truper, H. G., Dahl, C.

Enzymology and molecular biology of prokaryotic sulfite oxidation (2001)

Kappler, U., Dahl, C.

Despite its toxicity, sulfite plays a key role in oxidative sulfur metabolism and there are even some microorganisms which can use it as sole electron source. Sulfite is the main intermediate in the...

Evidence for two pathways of thiosulfate oxidation in Starkeya novella (formerly Thiobacillus novellus) (2001)

Kappler, U., Friedrich, C. G., Truper, H. G., Dahl, C.

The pathway of thiosulfate oxidation in the facultatively chemolithotrophic, sulfur-oxidizing bacterium Starkeya novella (formerly Thiobacillus novellus) has not been established beyond doubt....

Sulfite : Cytochrome c oxidoreductase from Thiobacillus novellus - Purification, characterization, and molecular biology of a heterodimeric member of the sulfite oxidase family (2000)

Kappler, U, Bennett, B, Rethmeier, J, Schwarz, G, Deutzmann, R, McEwan, AG, ...

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by...

Sulfite: Cytochrome c oxidoreductase from Thiobacillus novellus (2000)

Kappler, U., Bennett, B., Reithmeier, J., Schwarz, G., Deutzmann, R., McEwan, A. G., ...

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by...

Sulfite : Cytochrome c oxidoreductase from Thiobacillus novellus - Purification, characterization, and molecular biology of a heterodimeric member of the sulfite oxidase family (2000)

Kappler, U, Bennett, B, Rethmeier, J, Schwarz, G, Deutzmann, R, McEwan, AG, ...

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by...

Sulfite: Cytochrome c oxidoreductase from Thiobacillus novellus (2000)

Kappler, U., Bennett, B., Reithmeier, J., Schwarz, G., Deutzmann, R., McEwan, A. G., ...

Direct oxidation of sulfite to sulfate occurs in various photo- and chemotrophic sulfur oxidizing microorganisms as the final step in the oxidation of reduced sulfur compounds and is catalyzed by...