Literature summary extracted from
Boll, M.; Einsle, O.; Ermler, U.; Kroneck, P.M.H.; Ullmann, G.M.
Structure and function of the unusual tungsten enzymes acetylene hydratase and class II benzoyl-coenzyme A reductase (2016), J. Mol. Microbiol. Biotechnol., 26, 119-137 .
Crystallization (Commentary)
EC Number |
Crystallization (Comment) |
Organism |
---|
4.2.1.112 |
high resolution crystal structure determination of the W-dependent enzyme crystallized under the exclusion of dioxygen (N2/H2 (94%/6% v/v)) at 1.26 A resolution, PDB ID 2E7Z |
Syntrophotalea acetylenica |
Protein Variants
EC Number |
Protein Variants |
Comment |
Organism |
---|
4.2.1.112 |
C141S |
site-directed mutagenesis |
Syntrophotalea acetylenica |
4.2.1.112 |
D13A |
site-directed mutagenesis of catalytically important Asp13, a direct neighbor of the [4Fe-4S] coordinating Cys12, forms a close hydrogen bond of 2.41 A to the oxygen ligand of the W ion, the mutant shows significant loss of activity compared to wild-type |
Syntrophotalea acetylenica |
4.2.1.112 |
D13E |
site-directed mutagenesis of catalytically important Asp13, a direct neighbor of the [4Fe-4S] coordinating Cys12, forms a close hydrogen bond of 2.41 A to the oxygen ligand of the W ion, the mutant shows unaltered activity compared to wild-type |
Syntrophotalea acetylenica |
4.2.1.112 |
I142A |
site-directed mutagenesis, Ile142 is part of the hydrophobic ring that is proposed to form the substrate binding cavity at the end of the access tunnel towards the active site, its exchange against alanine results in a strong loss of activity |
Syntrophotalea acetylenica |
4.2.1.112 |
K48A |
site-directed mutagenesis of the residue involved in electron transfer between the two cofactors, the exchange of Lys48 against alanine does not affect catalysis |
Syntrophotalea acetylenica |
Inhibitors
EC Number |
Inhibitors |
Comment |
Organism |
Structure |
---|
4.2.1.112 |
cyanide |
a cyanide sensitive enzyme |
Syntrophotalea acetylenica |
|
4.2.1.112 |
additional information |
oxidation of AH with one equivalent [Fe(CN)6]3- |
Syntrophotalea acetylenica |
|
Localization
EC Number |
Localization |
Comment |
Organism |
GeneOntology No. |
Textmining |
---|
4.2.1.112 |
soluble |
the enzyme activity is localized exclusively in the soluble fraction of the cell extract |
Syntrophotalea acetylenica |
- |
- |
Metals/Ions
EC Number |
Metals/Ions |
Comment |
Organism |
Structure |
---|
4.2.1.112 |
Fe2+ |
in [4Fe-4S] cluster, the enzyme contains 3.7-3.9 mol Fe/mol enzyme |
Syntrophotalea acetylenica |
|
4.2.1.112 |
Molybdenum |
a Mo-dependent active form of AH (Mo-AH) can also be obtained from Pelobacter acetylenicus |
Syntrophotalea acetylenica |
|
4.2.1.112 |
additional information |
the dependence of AH activity on the applied redox potential gives a midpoint potential of -340 mV. Mo-dependent enzyme is approximately 10fold less active than the native W-dependent enzyme. W is generally preferred over Mo in low-potential redox catalysis |
Syntrophotalea acetylenica |
|
4.2.1.112 |
Tungsten |
bound with two pyranopterins, the enzyme contains 0.4-0.5 mol W/mol enzyme |
Syntrophotalea acetylenica |
|
Natural Substrates/ Products (Substrates)
EC Number |
Natural Substrates |
Organism |
Comment (Nat. Sub.) |
Natural Products |
Comment (Nat. Pro.) |
Rev. |
Reac. |
---|
4.2.1.112 |
acetylene + H2O |
Syntrophotalea acetylenica |
- |
acetaldehyde |
- |
r |
|
Organism
EC Number |
Organism |
UniProt |
Comment |
Textmining |
---|
4.2.1.112 |
Syntrophotalea acetylenica |
Q71EW5 |
- |
- |
Reaction
EC Number |
Reaction |
Comment |
Organism |
Reaction ID |
---|
4.2.1.112 |
acetaldehyde = acetylene + H2O |
acetylene hydratase harbors two pyranopterins bound to tungsten, and a [4Fe-4S] cluster. Tungsten is coordinated by four dithiolene sulfur atoms, one cysteine sulfur, and one oxygen ligand. The enzyme activity requires a strong reductant suggesting (IV) as the active oxidation state. Two different types of reaction pathways have been proposed, the reaction does not involve a net electron transfer. The nature of the oxygen ligand of the W center in the enzyme is crucial to formulate a reaction mechanism. Residue Asp13 is catalytically important because it activates the oxygen atom for the addition to the C-C triple bond. Reaction mechanism analysis, overview |
Syntrophotalea acetylenica |
|
Substrates and Products (Substrate)
EC Number |
Substrates |
Comment Substrates |
Organism |
Products |
Comment (Products) |
Rev. |
Reac. |
---|
4.2.1.112 |
acetylene + H2O |
- |
Syntrophotalea acetylenica |
acetaldehyde |
- |
r |
|
4.2.1.112 |
additional information |
the enzyme is highly specific for acetylene |
Syntrophotalea acetylenica |
? |
- |
? |
|
Subunits
EC Number |
Subunits |
Comment |
Organism |
---|
4.2.1.112 |
? |
x * 83500, about, mass spectrometry |
Syntrophotalea acetylenica |
4.2.1.112 |
More |
domain I (residues 4-60) harbors the [4Fe-4S] cluster, ligated by the four cysteine residues Cys9, Cys12, Cys16 and Cys46. Domains II (residues 65-136 and 393-542) and III (residues 137-327) have an alphabetaalpha-fold with homologies to the NAD-binding fold of dehydrogenases |
Syntrophotalea acetylenica |
Cofactor
EC Number |
Cofactor |
Comment |
Organism |
Structure |
---|
4.2.1.112 |
additional information |
cofactors bis-WPT guanine dinucleotide and [4Fe-4S] cluster are buried deep inside a four-domain fold, as typically observed for enzymes of the DMSOR family |
Syntrophotalea acetylenica |
|
4.2.1.112 |
tungsto-bis(pyranopterin guanine dinucleotide) |
the enzyme harbors two pyranopterins bound to tungsten, structure overview |
Syntrophotalea acetylenica |
|
4.2.1.112 |
[4Fe-4S] cluster |
low potential ferredoxin-type [4Fe-4S] cluster, the [4Fe-4S] has a midpoint potential around -410 mV |
Syntrophotalea acetylenica |
|
General Information
EC Number |
General Information |
Comment |
Organism |
---|
4.2.1.112 |
evolution |
the enzyme belongs to the tungsten containing enzymes, and is a member of the dimethyl sulfoxide reductase (DMSOR) family of enzymes. The W center coordinated by the two MGDs with the [4Fe-4S] cluster in close proximity, is unique for an enzyme of the DMSOR family |
Syntrophotalea acetylenica |
4.2.1.112 |
additional information |
Mo-dependent enzyme is approximately 10fold less active than the native W-dependent enzyme. Active site cavity structure of Pelobacter acetylenicus acetylene hydratase, overview. A C2H2 molecule docked computationally at the AH active site gives an excellent fit in the pocket of the hydrophobic ring with its carbon atoms positioned directly above the oxygen ligand and the carboxylic acid group of active site residue Asp13 |
Syntrophotalea acetylenica |