Cloned (Comment) | Organism |
---|---|
gene SRX, overexpression of recombinant His-tagged full-length enzyme in Escherichia coli strain BL21(DE3) | Arabidopsis thaliana |
Crystallization (Comment) | Organism |
---|---|
purified enzyme AtSrx in complex with ADP, sitting drop vapor diffusion method, mixing of 0.001 ml of 20 mg/ml protein in 50 mM Tris-HCl, pH 7.5, 50 mM NaCl, and 1 mM DTT, with 0.001 ml of well solution containing 0.8 M NaH2PO4/1.2M KH2PO4, and acetate, pH 4.5, at 16°C, 1 week, X-ray diffraction structure determination and analysis at 3.20 A resolution | Arabidopsis thaliana |
Protein Variants | Comment | Organism |
---|---|---|
C72S | site-directed mutagenesis, the cysteine-deficient mutation at the active completely abolishes activity of Srx | Arabidopsis thaliana |
R28Q | site-directed mutagenesis, the mutation in AtSrx only partially reduces its activity and needs the additional mutation of E76 to totally inactivation. The survived activity of AtSrx may be the result of that AtSrx has two more arginine residues at the loop next to alpha1. The side chains of Arg32 and Arg34, which can swing to the side of Cys72, may partially compensate for the effects of the loss of Arg28 | Arabidopsis thaliana |
R28Q/E76A | site-directed mutagenesis, the double mutation disrupts the stability of the loop in which Arg32/Arg34 is located, therefore AtSrx is completely inactivated | Arabidopsis thaliana |
Localization | Comment | Organism | GeneOntology No. | Textmining |
---|---|---|---|---|
chloroplast | residues 1-22 of AtSrx are predicted as a chloroplast-targeting transit peptide | Arabidopsis thaliana | 9507 | - |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Arabidopsis thaliana |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | Arabidopsis thaliana | AtSrx has sulfinic acid reductase activity to catalyze the reduction of the overoxidized form of 2-Cys Prx in vitro and in vivo | ? | - |
- |
|
peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH | Arabidopsis thaliana | - |
peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Arabidopsis thaliana | Q8GY89 | - |
- |
Purification (Comment) | Organism |
---|---|
recombinant His-tagged full-length enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography, ultrafiltration, and gel filtration | Arabidopsis thaliana |
Source Tissue | Comment | Organism | Textmining |
---|---|---|---|
leaf | - |
Arabidopsis thaliana | - |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
additional information | AtSrx has sulfinic acid reductase activity to catalyze the reduction of the overoxidized form of 2-Cys Prx in vitro and in vivo | Arabidopsis thaliana | ? | - |
- |
|
additional information | AtSrx has sulfinic acid reductase activity to catalyze the reduction of the overoxidized form of 2-Cys Prx in vitro and in vivo. Overall structure of ADP-bound AtSrx, ADP is bound at a positive charged pocket of AtSrx, detailed overview. AtSrx forms a complex with AtPrxA in vitro, modeling | Arabidopsis thaliana | ? | - |
- |
|
peroxiredoxin-(S-hydroxy-S-oxocysteine) + ATP + 2 R-SH | - |
Arabidopsis thaliana | peroxiredoxin-(S-hydroxycysteine) + ADP + phosphate + R-S-S-R | - |
? |
Synonyms | Comment | Organism |
---|---|---|
AtSrx | - |
Arabidopsis thaliana |
Cofactor | Comment | Organism | Structure |
---|---|---|---|
ATP | - |
Arabidopsis thaliana |
Organism | Comment | pI Value Maximum | pI Value |
---|---|---|---|
Arabidopsis thaliana | sequence calculation | - |
9.86 |
Organism | Comment | Expression |
---|---|---|
Arabidopsis thaliana | under the oxidation stress elicited by hydrogen peroxide, the transcription level of AtSrx is significantly increased | up |
General Information | Comment | Organism |
---|---|---|
evolution | AtSrx has more positive charges than human enzyme HsSrx. The theoretical pI of AtSrx is 9.86, much higher than 5.47 of HsSrx. There are 10 arginine residues and 7 lysine residues in AtSrx but only 5 arginine residues and 3 lysine residues in HsSrx. For negatively charged amino acids residues, there are 6 glutamic acid residues and 4 aspartic acid residues in AtSrx, while there are 2 glutamic acid residues and 8 aspartic acid residues in HsSrx. Abundant charged amino acids of AtSrx provide more positive charge at ADP binding pocket and more interaction with active | Arabidopsis thaliana |
additional information | the crystal structure of sulfiredoxin from Arabidopsis thaliana (AtSrx) displays a typical ParB/Srx fold with an ATP bound at a conservative nucleotide binding motif GCHR. Both the ADP binding pocket and the putative AtSrx-AtPrxA interaction surface of AtSrx are more positively charged comparing to HsSrx, suggesting a robust mechanism of AtSrx. Complex formation analysis of enzyme AtSrx with wild-type and F149Q/C241S mutant AtPrxA substrates | Arabidopsis thaliana |
physiological function | 2-Cys peroxiredoxins (Prxs) are highly abundant peroxidases that play as peroxide sensors promoting H2O2 signaling and oxidative stress resistance in respond to elevated oxidative levels. Prxs use a peroxidatic cysteine (Cys-SpH) to catalytically decompose peroxides. During normal catalysis, the peroxidatic Cys residue (Cys-SpH) is oxidized to Cys sulfenic acid (Cys-SpOH) and further inactivation by peroxidation of the peroxidatic cysteine residue to Cys sulfinic acid (Cys-SpO2-). Importantly, Prxs can be reactivated with the Cys-SPO2- moiety reduced to Cys sulfenic acid (Cys-SpOH) by a repaired enzyme known as sulfiredoxin (Srx). This reversible event is a physiologically important process against the oxidative stress that can allow cells to return to homeostasis | Arabidopsis thaliana |