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Literature summary for 1.8.4.2 extracted from
- Identification of a thiol-disulfide oxidoreductase (SdbA) catalyzing disulfide bond formation in the superantigen SpeA in Streptococcus pyogenes (2021), J. Bacteriol., 203, e0015321 .
Cloned(Commentary)
| Cloned (Comment) | Organism |
|---|---|
| gene sdbA, recombinant expression of N-terminally His6-tagged wild-type and mutant enzymes in Escherichia coli strain XL-1 Blue | Streptococcus pyogenes |
Protein Variants
| Protein Variants | Comment | Organism |
|---|---|---|
| C46A | site-directed mutagenesis | Streptococcus pyogenes |
| C49A | site-directed mutagenesis, SdbAC49A forms a mixed disulfide with SpeAC87A | Streptococcus pyogenes |
| additional information | generation of a sdbA-knockout mutant by insertional inactivation using pG1host5 carrying an internal portion of the gene. SpeA in the culture supernatant remains reduced when gene sdbA is inactivated and restored to the oxidized state when a functional copy of sdbA is returned to the sdbA-knockout mutant. Complementation of sdbA deletion restores SpeA to an oxidized state | Streptococcus pyogenes |
Localization
| Localization | Comment | Organism | GeneOntology No. | Textmining |
|---|---|---|---|---|
| cell wall | - |
Streptococcus pyogenes | 5618 | - |
| additional information | SdbA does not have a predicted signal peptide or transmembrane domain | Streptococcus pyogenes | - |
- |
Natural Substrates/ Products (Substrates)
| Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| SdbA carrying a disulfide bond + superantigen SpeA with reduced L-cysteine residues | Streptococcus pyogenes | - |
SdbA with reduced L-cysteine residues + superantigen SpeA carrying a disulfide bond | - |
? |  |
Organism
| Organism | UniProt | Comment | Textmining |
|---|---|---|---|
| Streptococcus pyogenes | - |
- |
- |
Purification (Commentary)
| Purification (Comment) | Organism |
|---|---|
| recombinant N-terminally His6-tagged wild-type and mutant enzymes from Escherichia coli strain XL-1 Blue by nickel affinity chromatography | Streptococcus pyogenes |
Substrates and Products (Substrate)
| Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
|---|---|---|---|---|---|---|
| SdbA carrying a disulfide bond + superantigen SpeA with reduced L-cysteine residues | - |
Streptococcus pyogenes | SdbA with reduced L-cysteine residues + superantigen SpeA carrying a disulfide bond | - |
? | |
| SdbA carrying a disulfide bond + superantigen SpeA with reduced L-cysteine residues | the superantigen SpeA contains 3 cysteine residues (Cys 87, Cys90, and Cys98) and has a disulfide bond formed between Cys87 and Cys98 | Streptococcus pyogenes | SdbA with reduced L-cysteine residues + superantigen SpeA carrying a disulfide bond | - |
? | |
Synonyms
| Synonyms | Comment | Organism |
|---|---|---|
| disulfide bond-forming thiol-disulfide oxidoreductase | - |
Streptococcus pyogenes |
| SdbA | - |
Streptococcus pyogenes |
| SpyM18_2037 | - |
Streptococcus pyogenes |
| TDOR | - |
Streptococcus pyogenes |
| thiol-disulfide oxidoreductase | - |
Streptococcus pyogenes |
General Information
| General Information | Comment | Organism |
|---|---|---|
| malfunction | SpeA in the culture supernatant remains reduced when gene sdbA is inactivated and restored to the oxidized state when a functional copy of sdbA is returned to the sdbA-knockout mutant. Complementation of sdbA deletion restores SpeA to an oxidized state. The enzyme mutant SdbAC49A forms a mixed disulfide with substrate mutant SpeAC87A. No reactions between SdbAC49A and SpeAC98A, SdbAC46A and SpeAC87A, or SdbAC46A and SpeAC98A | Streptococcus pyogenes |
| physiological function | SpyM18_2037, named SdbA, is the catalyst that introduces the disulfide bond in SpeA. Enzyme SdbA has a typical C46XXC49 active site motif commonly found in TDORs. The cysteines in the CXXC motif are required for the disulfide bond in SpeA to form. Interactions between SdbA and SpeA are examined using cysteine variant proteins. The results show that SdbAC49A forms a mixed disulfide with SpeAC87A, suggesting that the N-terminal Cys46 of SdbA and the C-terminal Cys98 of SpeA participate in the initial reaction. SpeA oxidized by SdbA displays biological activities suggesting that SpeA is properly folded following oxidation by SdbA. The enzyme substrate superantigen exotoxin A, SpeA (25 kDa) contains three cysteine residues (Cys87, Cys90, and Cys98). In the crystal structure of SpeA, Cys87 and Cys98 are linked by a disulfide bond. The disulfide bond and neighboring amino acids form a socalled disulfide loop, which is a conserved feature in all staphylococcal enterotoxins except the toxic shock syndrome toxin 1 (TSST-1). The importance of the disulfide bond in SpeA and staphylococcal enterotoxins (e.g. SEC2). SpeA and other streptococcal and staphylococcal superantigens are able to bind simultaneously to the major histocompatibility complex (MHC) class II molecules and the T-cell receptors, resulting in T cell activation and massive cytokine production | Streptococcus pyogenes |
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