GO:0004781 sulfate adenylyltransferase (ATP) activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0004781 sulfate adenylyltransferase (ATP) activity catalyzes the reaction sulfate + ATP + H+ = adenosine 5'-phosphosulfate (APS) + diphosphate, the first committed step of sulfate assimilation.
• The enzyme is also known as ATP sulfurylase and is essential for the biosynthesis of activated sulfate donors such as PAPS (3'-phosphoadenosine 5'-phosphosulfate) [3,8].
• In humans, ATP sulfurylase is a bifunctional enzyme (PAPSS1/PAPSS2) that also catalyzes APS phosphorylation to PAPS; deficiency causes skeletal and connective tissue disorders.
• In plants and cyanobacteria, ATP sulfurylase activity is regulated by sulfur availability and growth conditions, linking environmental cues to thiol metabolism [5,7].
• The reaction is reversible in vitro but physiologically directed toward APS formation, and it is a validated target for metabolic engineering of PAPS production.
• CRISPR-based knockout, point-mutation, and knock-in models enable causal dissection of ATP sulfurylase function in sulfur metabolism and disease.
Description
Sulfate adenylyltransferase (ATP) activity, encoded by GO:0004781, is a molecular function that catalyzes the adenylation of sulfate to form adenosine 5'-phosphosulfate (APS) and pyrophosphate, using ATP as the adenosyl donor. This reaction is the first committed step in the sulfate assimilation pathway and is therefore a key control point for the production of reduced sulfur compounds and activated sulfate esters [3,8]. The enzyme is widely distributed across bacteria, archaea, fungi, plants, and animals, and its activity is essential for the biosynthesis of cysteine, methionine, and sulfated biomolecules [7,8]. In humans, the enzyme exists as bifunctional PAPS synthases (PAPSS1 and PAPSS2) that couple APS formation to APS phosphorylation, producing the universal sulfate donor PAPS. Mutations in PAPSS2 cause spondyloepimetaphyseal dysplasia and other skeletal dysplasias, highlighting the clinical importance of this activity. In plants and cyanobacteria, ATP sulfurylase is a regulated entry point for sulfur assimilation, and its activity changes in response to sulfur availability and growth conditions [5,7]. Because of its central role in sulfur metabolism, ATP sulfurylase is a target for metabolic engineering, structural biology, and drug discovery [3,4,6]. This article summarizes the definition, mechanism, key genes, disease links, and research methods for GO:0004781, with a focus on how CRISPR-based models can be used to study its function.
sulfate adenylyltransferase (ATP) activity At A Glance
| GO ID | GO:0004781 |
|---|---|
| GO term | sulfate adenylyltransferase (ATP) activity |
| Ontology | molecular_function |
| Synonym | ATP sulfurylase activity; sulfate adenylate transferase activity; adenylylsulfate pyrophosphorylase activity; adenosine-5'-triphosphate sulfurylase activity |
| Major function | Catalyzes the formation of adenosine 5'-phosphosulfate (APS) from sulfate and ATP, the first step of sulfate assimilation |
| Reaction | sulfate + ATP + H+ = adenosine 5'-phosphosulfate + diphosphate |
| Cofactors | Mg2+ or other divalent metal ions are typically required for catalysis |
| Pathway context | Sulfur metabolism; sulfate assimilation; PAPS biosynthesis |
| Human genes | PAPSS1, PAPSS2 (bifunctional PAPS synthases with ATP sulfurylase and APS kinase activities) |
What Is GO:0004781?
GO:0004781 sulfate adenylyltransferase (ATP) activity is defined as the catalysis of the reaction: sulfate + ATP + H+ = adenosine 5'-phosphosulfate + diphosphate. In other words, it is the enzyme activity that transfers an adenylyl group from ATP to sulfate, producing APS and releasing pyrophosphate. This activity is synonymous with ATP sulfurylase, sulfate adenylate transferase, and adenylylsulfate pyrophosphorylase, among other names.
Why Is sulfate adenylyltransferase (ATP) activity Important in Cell Biology?
GO:0004781 is important because it initiates the sulfate assimilation pathway, which provides reduced sulfur for cysteine and methionine biosynthesis and generates activated sulfate for sulfation reactions [3,8]. In humans, the bifunctional PAPS synthases that harbor this activity are essential for the sulfation of glycosaminoglycans, steroids, and xenobiotics, and their deficiency causes skeletal and connective tissue disorders. In plants and microbes, ATP sulfurylase activity is a key determinant of sulfur use efficiency and is regulated by sulfur status [5,7]. The enzyme is also a target for metabolic engineering of PAPS production and for the development of antimicrobial and herbicidal compounds.
• Catalyzes the first committed step of sulfate assimilation, linking inorganic sulfate to organic sulfur metabolism.
• Required for the biosynthesis of PAPS, the universal sulfate donor for sulfotransferases.
• Human PAPSS2 mutations cause spondyloepimetaphyseal dysplasia and other skeletal dysplasias.
• Regulates thiol contents in plants and affects stress responses and nutritional quality.
• Activity changes with growth conditions in cyanobacteria, linking environmental sulfur to primary metabolism.
• Target for metabolic engineering of PAPS production from ATP and sulfate.
• Provides a model system for studying enzyme mechanism and allosteric regulation [3,6].
• Potential drug target in pathogens that rely on sulfate assimilation for survival.
What Happens During sulfate adenylyltransferase (ATP) activity?
Substrate binding and adenylation
In simple terms: The enzyme grabs sulfate and ATP and joins them together.
The reaction begins with the binding of sulfate and ATP to the active site of ATP sulfurylase. The enzyme catalyzes the nucleophilic attack of sulfate on the alpha-phosphate of ATP, forming adenosine 5'-phosphosulfate (APS) and releasing pyrophosphate (PPi). This step is reversible in vitro, but in vivo the reaction is driven forward by the subsequent hydrolysis of pyrophosphate or by the rapid consumption of APS in downstream reactions [3,8].
APS formation and downstream conversion
In simple terms: The product APS is either reduced to make sulfur-containing amino acids or phosphorylated to make PAPS.
APS is a branch-point metabolite. In plants and bacteria, APS is reduced by APS reductase to sulfite, which is then incorporated into cysteine. In humans and other animals, APS is phosphorylated by APS kinase to form PAPS, the activated sulfate donor used by sulfotransferases. The bifunctional PAPS synthases (PAPSS1 and PAPSS2) couple ATP sulfurylase and APS kinase activities, channeling APS directly to PAPS.
Regulation by sulfur availability
In simple terms: When sulfur is scarce, the cell adjusts how much of this enzyme is active.
In plants and cyanobacteria, ATP sulfurylase activity is regulated in response to sulfur availability. For example, changes in growth conditions alter ATP sulfurylase activity in cyanobacteria, reflecting a metabolic adaptation to sulfur status. In plants, manipulation of thiol contents can affect the expression and activity of sulfate assimilation enzymes, including ATP sulfurylase.
Structural and mechanistic features
In simple terms: The enzyme has a specific shape that allows it to hold sulfate and ATP in the right position.
Structural studies of related enzymes, such as APS kinase from Archaeoglobus fulgidus, have provided insights into the architecture of the sulfate activation pathway. ATP sulfurylase belongs to the nucleotidylyl transferase superfamily and typically requires divalent metal ions such as Mg2+ for catalysis. The enzyme can be immobilized for biotechnological applications, as demonstrated by a protein crystalline inclusion-based system for PAPS biosynthesis from ATP and sulfate.
Key Genes Involved in GO:0004781 sulfate adenylyltransferase (ATP) activity
The following genes encode proteins that carry or are directly associated with sulfate adenylyltransferase (ATP) activity across species.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PAPSS1 | Human bifunctional PAPS synthase 1 with ATP sulfurylase and APS kinase activities | Studying PAPS biosynthesis and sulfation in human cells |
| PAPSS2 | Human bifunctional PAPS synthase 2; mutations cause skeletal dysplasia | Disease modeling and structure-function studies |
| MET3 | Saccharomyces cerevisiae ATP sulfurylase | Model for sulfate assimilation and regulation |
| cysN | Escherichia coli ATP sulfurylase subunit | Bacterial sulfate assimilation and antibiotic target studies |
| cysD | Escherichia coli ATP sulfurylase subunit | Bacterial sulfate assimilation and antibiotic target studies |
| APS1 | Arabidopsis thaliana ATP sulfurylase isoform | Plant sulfur metabolism and thiol regulation |
| APS2 | Arabidopsis thaliana ATP sulfurylase isoform | Plant sulfur metabolism and thiol regulation |
| APS3 | Arabidopsis thaliana ATP sulfurylase isoform | Plant sulfur metabolism and thiol regulation |
| APS4 | Arabidopsis thaliana ATP sulfurylase isoform | Plant sulfur metabolism and thiol regulation |
| sat | Cyanobacterial ATP sulfurylase | Linking growth conditions to sulfur assimilation |
| nodP | Rhizobium meliloti ATP sulfurylase | Symbiotic nitrogen fixation and sulfur metabolism |
| nodQ | Rhizobium meliloti ATP sulfurylase | Symbiotic nitrogen fixation and sulfur metabolism |
| PAPSS | Fungal bifunctional PAPS synthase | Antifungal target and sulfur metabolism |
| ATPS | Generic ATP sulfurylase in various organisms | Enzyme kinetics and inhibitor studies |
| PAPSS2A | Zebrafish PAPS synthase 2a | Developmental skeletal studies |
| PAPSS2B | Zebrafish PAPS synthase 2b | Developmental skeletal studies |
| SULT | Sulfotransferases that consume PAPS | Downstream of ATP sulfurylase activity |
How Is sulfate adenylyltransferase (ATP) activity Regulated?
ATP sulfurylase activity is regulated at multiple levels. In plants and cyanobacteria, sulfur availability modulates enzyme activity and gene expression, with changes in growth conditions altering ATP sulfurylase activity. In plants, manipulation of thiol contents affects the expression of sulfate assimilation genes, including ATP sulfurylase. In humans, PAPSS2 expression is regulated during chondrocyte differentiation, and mutations in PAPSS2 cause skeletal dysplasia. The bifunctional nature of PAPS synthases allows channeling of APS to PAPS, which may be regulated by APS levels and by the interaction between the ATP sulfurylase and APS kinase domains.
sulfate adenylyltransferase (ATP) activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PAPSS2 | Spondyloepimetaphyseal dysplasia; skeletal dysplasia | Knockout or point-mutation in human chondrocytes or zebrafish |
| PAPSS1 | Sulfation disorders; altered drug metabolism | Knockout in HepG2 cells for sulfation studies |
| MET3 | Fungal sulfur metabolism; antifungal target | Knockout in Candida albicans or Aspergillus |
| cysN/cysD | Bacterial sulfate assimilation; antibiotic target | Knockout in E. coli or Salmonella |
| APS1 | Plant sulfur metabolism; nutritional quality | Knockout in Arabidopsis thaliana |
Skeletal dysplasia and PAPSS2 deficiency
Biallelic mutations in PAPSS2, which encodes a bifunctional enzyme with ATP sulfurylase and APS kinase activities, cause spondyloepimetaphyseal dysplasia (SEMD) and other skeletal dysplasias. These disorders are characterized by abnormal cartilage and bone development due to impaired sulfation of glycosaminoglycans, which require PAPS produced by the ATP sulfurylase step.
Sulfation disorders and drug metabolism
Because ATP sulfurylase activity is required for PAPS synthesis, its dysfunction can affect the sulfation of steroids, xenobiotics, and neurotransmitters. PAPS deficiency can lead to impaired drug metabolism and altered hormone homeostasis. The enzyme is therefore relevant to pharmacogenomics and endocrine disorders.
Infectious disease targets
Many pathogenic bacteria and fungi rely on sulfate assimilation for survival and virulence. ATP sulfurylase is essential in these organisms, making it a potential target for antimicrobial and antifungal drug development. Inhibitors of ATP sulfurylase could disrupt sulfur metabolism and inhibit pathogen growth.
From sulfate adenylyltransferase (ATP) activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of ATP sulfurylase activity affect PAPS levels and sulfation? | CRISPR knockout of PAPSS1/PAPSS2 in human cell lines |
| What is the effect of a specific point mutation on enzyme kinetics? | CRISPR point mutation of catalytic residues in PAPSS2 |
| Can a tagged version of ATP sulfurylase be used to study localization? | Knock-in of GFP or FLAG tag at the endogenous locus |
| Does overexpression of ATP sulfurylase increase PAPS production? | Overexpression of PAPSS1 or PAPSS2 in HEK293 or CHO cells |
| What is the role of ATP sulfurylase in plant sulfur assimilation? | Knockout or overexpression of APS isoforms in Arabidopsis |
| How does ATP sulfurylase activity change with growth conditions? | CRISPR interference or knockout in cyanobacteria |
How to Study the sulfate adenylyltransferase (ATP) activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| HPLC activity assay | ATP sulfurylase enzyme activity | Quantifying activity in tissue or cell lysates |
| Coupled spectrophotometric assay | APS or pyrophosphate production | High-throughput screening of inhibitors |
| X-ray crystallography | Three-dimensional structure of enzyme-substrate complexes | Mechanistic studies and inhibitor design |
| CRISPR knockout | Loss-of-function phenotype | Determining essentiality and pathway role |
| CRISPR point mutation | Effect of specific amino acid changes | Validating catalytic residues and disease variants |
| Knock-in tagging | Protein localization and interactions | Live-cell imaging and proteomics |
| Overexpression | Gain-of-function effects | Increasing PAPS production for biotechnology |
Enzymatic activity assays
ATP sulfurylase activity can be measured using coupled assays that detect APS formation or pyrophosphate release. A high-performance liquid chromatography (HPLC) method has been developed for assaying ATP-sulfurylase activity from rat liver, providing a reliable way to quantify enzyme activity in biological samples. Such assays are essential for characterizing mutant enzymes and for screening inhibitors.
Structural biology and crystallography
Crystal structures of related enzymes, such as APS kinase from Archaeoglobus fulgidus, have revealed key features of the sulfate activation pathway. Structural studies of ATP sulfurylase and its complexes with substrates and inhibitors can guide the design of specific inhibitors and help interpret disease-causing mutations.
Metabolic engineering and immobilization
ATP sulfurylase can be used in vitro for the biosynthesis of PAPS from ATP and sulfate. A protein crystalline inclusion-based enzyme immobilization system has been developed for this purpose, enabling efficient PAPS production. Such systems are useful for producing PAPS for sulfotransferase reactions and for studying enzyme kinetics.
Genetic and genomic approaches
CRISPR/Cas9 genome editing enables the creation of knockout, point-mutation, and knock-in models to study ATP sulfurylase function. For example, ribonucleoprotein-based CRISPR/Cas9 co-editing has been used in Aspergillus luchuensis mut. kawachii to modify genes involved in sulfur metabolism. These approaches can be combined with RNA-seq and proteomics to assess downstream effects on sulfur metabolism and sulfation.
How CRISPR Can Be Used to Study GO:0004781 sulfate adenylyltransferase (ATP) activity
Knockout
CRISPR knockout of genes encoding ATP sulfurylase, such as PAPSS1, PAPSS2, MET3, or cysN/cysD, can abolish enzyme activity and reveal its role in sulfur metabolism, PAPS production, and downstream sulfation [1,8]. Knockout models are useful for assessing essentiality and for identifying compensatory pathways.
Point Mutation
CRISPR point mutation can be used to introduce specific amino acid substitutions into the active site of ATP sulfurylase to test catalytic mechanism and to model human disease variants, such as those found in PAPSS2 deficiency. This approach allows precise structure-function analysis without altering the rest of the genome.
Knock-in
Knock-in of epitope tags (e.g., GFP, FLAG) or reporter genes at the endogenous ATP sulfurylase locus enables real-time tracking of protein expression, localization, and interactions. Tagged knock-in models are valuable for studying the spatiotemporal regulation of sulfate assimilation.
Overexpression
CRISPR activation or transgenic overexpression of ATP sulfurylase genes can increase PAPS production and enhance sulfation capacity in cells. Overexpression models are used in metabolic engineering to boost the biosynthesis of sulfated compounds and to study the effects of elevated enzyme activity on sulfur metabolism.
How EDITGENE Supports sulfate adenylyltransferase (ATP) activity Research
Researchers studying sulfate adenylyltransferase (ATP) activity-related genes often need to determine whether a candidate gene is causally involved in sulfur metabolism, PAPS production, or disease phenotypes. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, enabling rigorous functional studies of GO:0004781 and its associated pathways.
Contact EDITGENE today to design your custom CRISPR model for sulfate adenylyltransferase (ATP) activity research.
Frequently Asked Questions About sulfate adenylyltransferase (ATP) activity
What is sulfate adenylyltransferase (ATP) activity?
It is the enzyme activity defined by GO:0004781 that catalyzes the reaction sulfate + ATP + H+ = adenosine 5'-phosphosulfate + diphosphate, also known as ATP sulfurylase.
What genes are involved in sulfate adenylyltransferase (ATP) activity?
Key genes include PAPSS1 and PAPSS2 in humans, MET3 in yeast, cysN and cysD in bacteria, and APS1-APS4 in plants [3,7,8].
What is the role of ATP sulfurylase in sulfur metabolism?
It catalyzes the first step of sulfate assimilation, producing APS, which is either reduced to sulfite or phosphorylated to PAPS [3,8].
How is ATP sulfurylase activity measured?
Activity can be measured by HPLC-based assays that detect APS formation or by coupled spectrophotometric assays.
What diseases are associated with ATP sulfurylase deficiency?
Mutations in PAPSS2 cause spondyloepimetaphyseal dysplasia and other skeletal dysplasias due to impaired PAPS production.
Can CRISPR be used to study ATP sulfurylase?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models allow precise functional studies of ATP sulfurylase genes.
What is the difference between ATP sulfurylase and APS kinase?
ATP sulfurylase produces APS from sulfate and ATP, while APS kinase phosphorylates APS to PAPS; in humans, both activities reside in bifunctional PAPS synthases.
Is ATP sulfurylase a drug target?
In pathogens that rely on sulfate assimilation, ATP sulfurylase is a potential antimicrobial target.
How is ATP sulfurylase regulated in plants?
Its activity is regulated by sulfur availability and thiol status, affecting cysteine and methionine biosynthesis.
What model organisms are used to study ATP sulfurylase?
Common models include Arabidopsis thaliana, Saccharomyces cerevisiae, Escherichia coli, cyanobacteria, and human cell lines [3,5,7,8].
Conclusion
GO:0004781 sulfate adenylyltransferase (ATP) activity is a fundamental molecular function that initiates sulfate assimilation and PAPS biosynthesis across all domains of life. Its central role in sulfur metabolism, human skeletal disease, and microbial pathogenesis makes it a compelling target for basic and translational research. CRISPR-based models, combined with enzymatic assays and structural biology, provide powerful tools to dissect its mechanism and regulation. EDITGENE offers comprehensive services to accelerate discovery in this field.
References
- 1. Karashima T et al.. 2025. Ribonucleoprotein-based CRISPR/Cas9 genome co-editing in Aspergillus luchuensis mut. kawachii.. J Biosci Bioeng 140(5):298-305 PMID: 40774862
- 2. Mina M et al.. 1988. Assay of ATP-sulfurylase activity from rat liver by high-performance liquid chromatography.. J Chromatogr 433:63-72 PMID: 2853170
- 3. Mueller JW et al.. 2013. Adenosine-5'-phosphosulfate--a multifaceted modulator of bifunctional 3'-phospho-adenosine-5'-phosphosulfate synthases and related enzymes.. FEBS J 280(13):3050-7 PMID: 23517310
- 4. Wang P et al.. 2023. Construction of a Protein Crystalline Inclusion-Based Enzyme Immobilization System for Biosynthesis of PAPS from ATP and Sulfate.. ACS Synth Biol 12(5):1487-1496 PMID: 37042633
- 5. Gastoldi L et al.. 2021. Changes in ATP Sulfurylase Activity in Response to Altered Cyanobacteria Growth Conditions.. Microbes Environ 36(2) PMID: 34039816
- 6. Kawakami T et al.. 2023. Crystal structure of adenosine 5'-phosphosulfate kinase isolated from Archaeoglobus fulgidus.. Biochem Biophys Res Commun 643:105-110 PMID: 36592583
- 7. Höfgen R et al.. 2001. Manipulation of thiol contents in plants.. Amino Acids 20(3):291-9 PMID: 11354605
- 8. Venkatachalam KV. 2003. Human 3'-phosphoadenosine 5'-phosphosulfate (PAPS) synthase: biochemistry, molecular biology and genetic deficiency.. IUBMB Life 55(1):1-11 PMID: 12716056
