This enzyme differs from EC 1.8.99.2, adenylyl-sulfate reductase, in using glutathione as the reductant. Glutathione can be replaced by gamma-glutamylcysteine or dithiothreitol, but not by thioredoxin, glutaredoxin or 2-sulfanylethan-1-ol (2-mercaptoethanol). The enzyme from the mouseear cress, Arabidopsis thaliana, contains a glutaredoxin-like domain. The enzyme is also found in other photosynthetic eukaryotes, e.g., the Madagascar periwinkle, Catharanthus roseus and the hollow green seaweed, Ulva intestinalis.
This enzyme differs from EC 1.8.99.2, adenylyl-sulfate reductase, in using glutathione as the reductant. Glutathione can be replaced by gamma-glutamylcysteine or dithiothreitol, but not by thioredoxin, glutaredoxin or 2-sulfanylethan-1-ol (2-mercaptoethanol). The enzyme from the mouseear cress, Arabidopsis thaliana, contains a glutaredoxin-like domain. The enzyme is also found in other photosynthetic eukaryotes, e.g., the Madagascar periwinkle, Catharanthus roseus and the hollow green seaweed, Ulva intestinalis.
GSH is docked into the AtAPR1 redox domain active site by manual docking, superimposing the structures of glutaredoxin bound with GSH on that of the AtAPR1 redox domain. The structure of cGrx1 complexed with GSH (PDB code 4TR1) is used as a template. Interaction between GSH and the AtAPR1 redox domain is analyzed, binding structure analysis, overview
APR is the key enzyme of sulfate assimilation, extensive posttranscriptional regulation of plant APR, e.g. by salt stress, sulfate assimilation pathway is controlled by a complex network of multiple signals on different regulatory levels, overview
APR is the key enzyme of sulfate assimilation, extensive posttranscriptional regulation of plant APR, e.g. by salt stress, sulfate assimilation pathway is controlled by a complex network of multiple signals on different regulatory levels, overview
dependent on, specific cofactor for the carboxyterminal glutathione-dependent reductase domain of the enzyme, can be exchanged for equally active DTT, glutathione is slightly inhibitory at high concentrations
all three APR isoforms increased 3fold in roots after 5 h of treatment with 150 mM NaCl, regulation of salt stress by plant hormone signalling, overview
in contrast to the cooperation of a sulfonucleotide reductase and a thioredoxin in prokaryote systems, in plants, the protein involved in the pathway is only a single polypeptide which consists of two distinct domains: a sulfonucleotide reductase-like one and a thioredoxin-like one
adenosine 5'-phosphosulfate (APS) reductase (APR) plays a vital role in catalyzing the reduction of activated sulfate to sulfite, which requires glutathione. APR activity is downregulated to avoid tissue injury by a negative feedback regulation, a mechanism associated with metabolic changes that cause reduced GSH concentration and the accumulation of sulfate
transgenic plants overexpressing APR2 show improved Cd tolerance, whereas knockout of APR2 have reduced Cd tolerance. APR2-overexpressing plants with increased Cd accumulation and tolerance show higher glutathione (GSH) and phytochelatin (PC) levels than the wild-type and apr2 mutant plants, but lower H2O2 and TBARS contents upon Cd exposure. Moreover, exogenous GSH application effectively rescued Cd hypersensitivity in APR2-knockout plants. Further analysis showed that buthionine sulfoximine (BSO, an inhibitor of GSH synthesis) treatment completely eliminated the enhanced Cd tolerance phenotypes of APR2-overexpressing plants, implying that APR2-mediated enhanced Cd tolerance is GSH-dependent. In addition, overexpression of the APR2 leads to elevated expressions of the GSH/PC synthesis related genes under Cd stress
in Arabidopsis there are three isoenzymes of APR (APR1, 2, and 3), of which APR2 is the major one in the sulfate reduction. Isozyme APR2 positively regulates cadmium tolerance through glutathione-dependent pathway
the C-terminal domain of APR acts as a glutathione-dependent reductase. The crystal structure of the C-terminal redox domain of Arabidopsis APR1 (AtAPR1) shows a conserved alpha/beta thioredoxin fold, but not a glutaredoxin fold, crystal structure analysis, folding of the AtAPR1 redox domain is measured by circular dichroism (CD) spectroscopy, overview. The C-terminal redox domain of APR is more similar to thioredoxin than glutaredoxin. Molecular model of AtAPR1 redox domain in complex with GSH, structure modeling, overview
overexpression of isoform Apr2 results in enhanced cotyledon greening and fresh weight increase when plants are treated with high glucose. A T-DNA insertion mutant line shows delayed greening and fresh weight growth inhibition in response to glucose and to 2-deoxyglucose. The expression of glucose responsive genes, hexokinase 1, phenylalanine ammonia lyase 1 and pathogenesis related gene 5, is elevated in Apr2-overexpressing and wild-type plants in response to glucose treatment, while in the T-DNA insertion mutant line the transcript level for these genes decreases. Apr2-overexpressing plants display delayed flowering under long day condition
APR2 regulates Cd accumulation and tolerance possibly through modulating GSH-dependent antioxidant capability and Cd-chelation machinery in Arabidopsis thaliana. APR2 can be exploited for engineering heavy metal-tolerant plants in phytoremediation. APR2-mediated enhanced Cd tolerance is GSH-dependent
chloroplast-localized adenosine-5'-phosphosulphate reductase (APR) generates sulfite and plays a pivotal role in reduction of sulfate to cysteine. The increases in APR activity in response to sulfite infiltration into wild-type and sulfite oxidase (SO)-deficient mutant leaves result in an increase in endogenous sulfite, indicating that APR has an important role in sulfite-induced increases in stomatal aperture. The importance of APR and SO and the significance of sulfite concentrations in water loss are further demonstrated during rapid, harsh drought stress in root-detached wild-type, gr2 and SO transgenic plants. Effects of sulfite infiltration on water status and sulfite accumulation in wild-type and sulfite oxidase overexpressing and deficient mutant leaves, overview
amino acid residues 73-327 form the R-domain which is homologous to microbial 5'-phosphoadenylylsulfate reductase, and of residues 328-465 form the C-domain which is homologous to thioredoxin, the domains alone are inactive, but mixing of both can partially rstore activity
amino acid residues 73-327 form the R-domain which is homologous to microbial 5'-phosphoadenylylsulfate reductase, and of residues 328-465 form the C-domain which is homologous to thioredoxin, the domains alone are inactive, but mixing of both can partially rstore activity
the recombinant detagged monomeric form of the AtAPR1 redox domain has 13 kDa measured by SDS-PAGE. Because plant APR1 is arranged as oligomers, this result implies that the oligomerization of AtAPR1 is not formed via redox domain self-interaction. The structure of the AtAPR1 redox domain is a compact spherical molecule comprising a central core of five-stranded beta-sheets flanked on either side by four helices. The fold of the redox domain arranged in the order beta1-alpha1-beta2-alpha2-beta3-alpha3-beta4-beta5-alpha4 is similar to the thioredoxin fold but not glutaredoxin fold. The N-terminal region begins with a short beta1 strand (residues Val4-Leu6), followed by alpha1 and beta2, consisting of residues Arg8 to Lys16 and Trp24 to Tyr29, respectively. The redox-active motif (Cys33-Pro34-Phe35-Cys36) is located at the N-terminal end of the alpha2-helix, consisting of residues Pro34 to Leu50. The strand beta3 comprises residues Lys56 to Arg61, followed by beta4 (Thr81-Phe85), beta5 (Ile93-Tyr95) and a C-terminal helix which consists of residues Lys99 to Glu111. Strands beta1, beta2, and beta3 are parallel, and strand beta4 is antiparallel to beta2 and beta5. Helices alpha1 and alpha3 pack on one side of the central beta-sheet, whereas helices alpha2 and alpha4 are located at opposite sides. The packing of the sandwich-like architecture is mainly maintained by hydrophobic interactions between the sheet and helices. Surface potential distribution of the redox domain shows most positive-charged residues around the redox-active motif
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CRYSTALLIZATION (Commentary)
ORGANISM
UNIPROT
LITERATURE
purified recombinant detagged C-terminal redox domain of AtAPR1, sitting drop vapor diffusion method, crystallization from 100 mM Tris, pH 7.0, 1.0 M sodium citrate, and 200 mM sodium chloride, at 10°C, 1 week, X-ray diffraction structure determination and analysis at 2.70 A resolution, structure modeling via molecular replacement method using the J-Trx1 fragment of protein disulfide reductase ERdj5 from Mus musculus (PDB entry 3APQ), as the template
gene APR1, the holoenzyme APR1p as well as the C-domain alone can complement the cysteine auxotrophy of an Escherichia coli cysH mutant strain, substituting for glutaredoxin, if the mutant is capable of producing glutathione, cysH encodes the 5'-phosphoadenylylsulfate reductase in Escherichia coli
gene APR1, the holoenzyme APR1p as well as the C-domain alone can complement the cysteine auxotrophy of an Escherichia coli cysH mutant strain, substituting for glutaredoxin, if the mutant is capable of producing glutathione, cysH encodes the 5'-phosphoadenylylsulfate reductase in Escherichia coli
construction of transgenic Arabidopsis thaliana plants expressing the active enzyme from Pseudomonas aeruginosa in the chloroplasts, the plants show reduced fresh and dry weight, delayed germination, smaller leaves, slightly reduced fertility, and increased enzyme activity and sulfate reduction accumulating of sulfite, thiosulfate, cysteine, gamma-glutamylcysteine, and glutathione, feeding of O-acetylserine leads to increased accumulation of sulfite and thiosulfate in the transgenic plants, phenotype alterations, overview
regulation of APR by NaCl is not affected in mutant plants deficient in the abscisic acid synthesis, but APR is induced in mutant plants deficient in jasmonate, salicylate, ethylene, cytokinin, and auxin signaling, while the enzyme activity remians unaltered, the induction by salt is abolished in mutant plants deficient in gibberellic acid signaling, overview
thermal denaturation of the AtAPR1 redox domain presents a highly thermoreversible property, melting temperature can be roughly estimated as 55°C. The secondary structure of the redox domain is greatly distorted on heating to 55°C by estimating from a series of CD spectra at various temperatures. The CD spectra for the AtAPR1 redox domain, which is 95°C thermal-denatured followed by cooling to 25°C, is almost identical to that of the native AtAPR1 redox domain measured at 25°C. This indicates that thermal denaturation of the redox domain is reversible
recombinant N-terminally GST-tagged C-terminal redox domain of AtAPR1 from Escherichia coli strain BL21(DE3) by glutahione affinity chromatography, the tag is cleaved off by thrombin, followed by gel filtration
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CLONED (Commentary)
ORGANISM
UNIPROT
LITERATURE
gene APR1, expression of the holoenzyme APR1p in Escherichia coli strain BL21(DE3), separate expression in Escherichia coli strain BL21(DE3) of amino acid residues 73-327, forming the R-domain, and of residues 328-465, forming the C-domain, the domains alone are inactive, but mixing of both can partially restore activity
gene APR2, quantitative real-time PCR isozyme expression analysis, analysis of transcript profiles of APR genes in Arabidopsis plants under Cd stress, changes in transcript levels of APR1, APR2, and APR3 at various time points in response to Cd exposure in Arabidopsis thaliana plants, overview. Transgenic overexpression of APR2 in Arabidopsis thaliana plants by Agrobacterium tumefaciens strain GV3101 transfection method
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EXPRESSION
ORGANISM
UNIPROT
LITERATURE
analysis of transcript profiles of APR genes in Arabidopsis plants under Cd stress, changes in transcript levels of APR1, APR2, and APR3 at various time points in response to Cd exposure in Arabidopsis thaliana plants, overview
Three members of a novel small gene-family from Arabidopsis thaliana able to complement functionally an Escherichia coli mutant defective in PAPS reductase activity encode proteins with a thioredoxin-like domain and "APS reductase" activity