Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
2-sulfoacetaldehyde + NADPH + H+ | Klebsiella oxytoca | - |
isethionate + NADP+ | - |
r |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Klebsiella oxytoca | D3U1D9 | - |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
2-sulfoacetaldehyde + NADPH + H+ | - |
Klebsiella oxytoca | isethionate + NADP+ | - |
r |
Subunits | Comment | Organism |
---|---|---|
homotetramer | in the tetrameric structure of IsfD, the respective diagonal subunits cross-interact strongly via their C-terminal tails. The latter region with beta-sheets 8 and 9 protrudes away from the main subunit body and reaches the active site of the opposite subunit. Thus, stabilization of the substrate-binding loop in the closed conformation is accomplished. In particular, C-terminal residue F248 is located close to side chains of active site amino acids I142 and Y148 of the diagonal subunit. This important interaction results in a proper positioning of Y148 for hydrogen bonding with the sulfonate group of isethionate. Enzyme structure comparisons, detailed overview | Klebsiella oxytoca |
Synonyms | Comment | Organism |
---|---|---|
IsfD | - |
Klebsiella oxytoca |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
NADP+ | - |
Klebsiella oxytoca | |
NADPH | binding structure analysis from crystal structure (PDB ID 6IXJ) | Klebsiella oxytoca |
General Information | Comment | Organism |
---|---|---|
evolution | among the dehydrogenases and reductases from taurine metabolism, only IsfD belongs to the short-chain dehydrogenase/reductase (SDR) superfamily. IsfD is closely related to YdfG from Escherichia coli (49% identical residues at 97% query cover) that has been characterized at first as serine dehydrogenase but functions also as malonic semialdehyde reductase in vivo | Klebsiella oxytoca |
metabolism | the enzyme catalyzes the reversible reduction in sulfoacetaldehyde to the corresponding alcohol isethionate. This is a key step in detoxification of the carbonyl intermediate formed in bacterial nitrogen assimilation from the alpha-aminoalkanesulfonic acid taurine. Bacterial taurine degradation is widespread, bacterial pathways for the degradation of taurine, overview | Klebsiella oxytoca |
additional information | structure-function analysis of IsfD, overview | Klebsiella oxytoca |
physiological function | like other aldehydes, sulfoacetaldehyde is potentially toxic and can be oxidized to sulfoacetate. In most taurine-degrading bacteria, however, it is reduced to the corresponding alcohol isethionate. In case this alcohol is excreted as the end product of taurine catabolism, the sulfur and carbon atoms are not assimilated. Although catalyzing serine and 3-hydroxypropionate oxidation as well, the role of IsfD in taurine metabolism and sulfoacetaldehyde reduction to isethionate is clearly corroborated by the operon-like association of the corresponding gene isfD together with genes encoding taurine uptake by transporter TauABC and deamination by transaminase Toa in Klebsiella oxytoca. There are physiological roles of IsfD-related SDR 3-hydroxyacid dehydrogenases | Klebsiella oxytoca |