Reaction participants Show >> << Hide
- Name help_outline formate Identifier CHEBI:15740 (CAS: 71-47-6) help_outline Charge -1 Formula CHO2 InChIKeyhelp_outline BDAGIHXWWSANSR-UHFFFAOYSA-M SMILEShelp_outline [H]C([O-])=O 2D coordinates Mol file for the small molecule Search links Involved in 99 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H+ Identifier CHEBI:15378 Charge 1 Formula H InChIKeyhelp_outline GPRLSGONYQIRFK-UHFFFAOYSA-N SMILEShelp_outline [H+] 2D coordinates Mol file for the small molecule Search links Involved in 9,717 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline H2 Identifier CHEBI:18276 (CAS: 1333-74-0) help_outline Charge 0 Formula H2 InChIKeyhelp_outline UFHFLCQGNIYNRP-UHFFFAOYSA-N SMILEShelp_outline [H][H] 2D coordinates Mol file for the small molecule Search links Involved in 21 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
- Name help_outline CO2 Identifier CHEBI:16526 (CAS: 124-38-9) help_outline Charge 0 Formula CO2 InChIKeyhelp_outline CURLTUGMZLYLDI-UHFFFAOYSA-N SMILEShelp_outline O=C=O 2D coordinates Mol file for the small molecule Search links Involved in 1,032 reaction(s) Find molecules that contain or resemble this structure Find proteins in UniProtKB for this molecule
Cross-references
RHEA:27610 | RHEA:27611 | RHEA:27612 | RHEA:27613 | |
---|---|---|---|---|
Reaction direction help_outline | undefined | left-to-right | right-to-left | bidirectional |
UniProtKB help_outline |
|
|||
MetaCyc help_outline | ||||
EcoCyc help_outline |
Publications
-
A bacterial hydrogen-dependent CO2 reductase forms filamentous structures.
Schuchmann K., Vonck J., Muller V.
Interconversion of CO2 and formic acid is an important reaction in bacteria. A novel enzyme complex that directly utilizes molecular hydrogen as electron donor for the reversible reduction of CO2 has recently been identified in the Wood-Ljungdahl pathway of an acetogenic bacterium. This pathway is ... >> More
Interconversion of CO2 and formic acid is an important reaction in bacteria. A novel enzyme complex that directly utilizes molecular hydrogen as electron donor for the reversible reduction of CO2 has recently been identified in the Wood-Ljungdahl pathway of an acetogenic bacterium. This pathway is utilized for carbon fixation as well as energy conservation. Here we describe the further characterization of the quaternary structure of this enzyme complex and the unexpected behavior of this enzyme in polymerizing into filamentous structures. Polymerization of metabolic enzymes into similar structures has been observed only in rare cases but the increasing number of examples point towards a more general characteristic of enzyme functioning. Polymerization of the purified enzyme into ordered filaments of more than 0.1 μm in length was only dependent on the presence of divalent cations. Polymerization was a reversible process and connected to the enzymatic activity of the oxygen-sensitive enzyme with the filamentous form being the most active state. << Less
-
Direct and reversible hydrogenation of CO2 to formate by a bacterial carbon dioxide reductase.
Schuchmann K., Muller V.
Storage and transportation of hydrogen is a major obstacle for its use as a fuel. An increasingly considered alternative for the direct handling of hydrogen is to use carbon dioxide (CO2) as an intermediate storage material. However, CO2 is thermodynamically stable, and developed chemical catalyst ... >> More
Storage and transportation of hydrogen is a major obstacle for its use as a fuel. An increasingly considered alternative for the direct handling of hydrogen is to use carbon dioxide (CO2) as an intermediate storage material. However, CO2 is thermodynamically stable, and developed chemical catalysts often require high temperatures, pressures, and/or additives for high catalytic rates. Here, we present the discovery of a bacterial hydrogen-dependent carbon dioxide reductase from Acetobacterium woodii directly catalyzing the hydrogenation of CO2. We also demonstrate a whole-cell system able to produce formate as the sole end product from dihydrogen (H2) and CO2 as well as syngas. This discovery opens biotechnological alternatives for efficient CO2 hydrogenation either by using the isolated enzyme or by employing whole-cell catalysis. << Less
-
Hydrogenation of CO<sub>2</sub> at ambient pressure catalyzed by a highly active thermostable biocatalyst.
Schwarz F.M., Schuchmann K., Muller V.
<h4>Background</h4>Replacing fossil fuels as energy carrier requires alternatives that combine sustainable production, high volumetric energy density, easy and fast refueling for mobile applications, and preferably low risk of hazard. Molecular hydrogen (H<sub>2</sub>) has been considered as promi ... >> More
<h4>Background</h4>Replacing fossil fuels as energy carrier requires alternatives that combine sustainable production, high volumetric energy density, easy and fast refueling for mobile applications, and preferably low risk of hazard. Molecular hydrogen (H<sub>2</sub>) has been considered as promising alternative; however, practical application is struggling because of the low volumetric energy density and the explosion hazard when stored in large amounts. One way to overcome these limitations is the transient conversion of H<sub>2</sub> into other chemicals with increased volumetric energy density and lower risk hazard, for example so-called liquid organic hydrogen carriers such as formic acid/formate that is obtained by hydrogenation of CO<sub>2</sub>. Many homogenous and heterogenous chemical catalysts have been described in the past years, however, often requiring high pressures and temperatures. Recently, the first biocatalyst for this reaction has been described opening the route to a biotechnological alternative for this conversion.<h4>Results</h4>The hydrogen-dependent CO<sub>2</sub> reductase (HDCR) is a highly active biocatalyst for storing H<sub>2</sub> in the form of formic acid/formate by reversibly catalyzing the hydrogenation of CO<sub>2</sub>. We report the identification, isolation, and characterization of the first thermostable HDCR operating at temperatures up to 70 °C. The enzyme was isolated from the thermophilic acetogenic bacterium <i>Thermoanaerobacter kivui</i> and displays exceptionally high activities in both reaction directions, substantially exceeding known chemical catalysts. CO<sub>2</sub> hydrogenation is catalyzed at mild conditions with a turnover frequency of 9,556,000 h<sup>-1</sup> (specific activity of 900 µmol formate min<sup>-1</sup> mg<sup>-1</sup>) and the reverse reaction, H<sub>2</sub> + CO<sub>2</sub> release from formate, is catalyzed with a turnover frequency of 9,892,000 h<sup>-1</sup> (930 µmol H<sub>2</sub> min<sup>-1</sup> mg<sup>-1</sup>). The HDCR of <i>T. kivui</i> consists of a [FeFe] hydrogenase subunit putatively coupled to a tungsten-dependent CO<sub>2</sub> reductase/formate dehydrogenase subunit by an array of iron-sulfur clusters.<h4>Conclusions</h4>The discovery of the first thermostable HDCR provides a promising biological alternative for a chemically challenging reaction and might serve as model for the better understanding of catalysts able to efficiently reduce CO<sub>2</sub>. The catalytic activity for reversible CO<sub>2</sub> hydrogenation of this enzyme is the highest activity known for bio- and chemical catalysts and requiring only ambient temperatures and pressures. The thermostability provides more flexibility regarding the process parameters for a biotechnological application. << Less
-
Membrane-anchored HDCR nanowires drive hydrogen-powered CO<sub>2</sub> fixation.
Dietrich H.M., Righetto R.D., Kumar A., Wietrzynski W., Trischler R., Schuller S.K., Wagner J., Schwarz F.M., Engel B.D., Muller V., Schuller J.M.
Filamentous enzymes have been found in all domains of life, but the advantage of filamentation is often elusive<sup>1</sup>. Some anaerobic, autotrophic bacteria have an unusual filamentous enzyme for CO<sub>2</sub> fixation-hydrogen-dependent CO<sub>2</sub> reductase (HDCR)<sup>2,3</sup>-which di ... >> More
Filamentous enzymes have been found in all domains of life, but the advantage of filamentation is often elusive<sup>1</sup>. Some anaerobic, autotrophic bacteria have an unusual filamentous enzyme for CO<sub>2</sub> fixation-hydrogen-dependent CO<sub>2</sub> reductase (HDCR)<sup>2,3</sup>-which directly converts H<sub>2</sub> and CO<sub>2</sub> into formic acid. HDCR reduces CO<sub>2</sub> with a higher activity than any other known biological or chemical catalyst<sup>4,5</sup>, and it has therefore gained considerable interest in two areas of global relevance: hydrogen storage and combating climate change by capturing atmospheric CO<sub>2</sub>. However, the mechanistic basis of the high catalytic turnover rate of HDCR has remained unknown. Here we use cryo-electron microscopy to reveal the structure of a short HDCR filament from the acetogenic bacterium Thermoanaerobacter kivui. The minimum repeating unit is a hexamer that consists of a formate dehydrogenase (FdhF) and two hydrogenases (HydA2) bound around a central core of hydrogenase Fe-S subunits, one HycB3 and two HycB4. These small bacterial polyferredoxin-like proteins oligomerize through their C-terminal helices to form the backbone of the filament. By combining structure-directed mutagenesis with enzymatic analysis, we show that filamentation and rapid electron transfer through the filament enhance the activity of HDCR. To investigate the structure of HDCR in situ, we imaged T. kivui cells with cryo-electron tomography and found that HDCR filaments bundle into large ring-shaped superstructures attached to the plasma membrane. This supramolecular organization may further enhance the stability and connectivity of HDCR to form a specialized metabolic subcompartment within the cell. << Less