GO:1990189 protein N-terminal-serine acetyltransferase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:1990189 describes the enzymatic activity that transfers an acetyl group from acetyl-CoA to the N-terminal serine residue of a protein, forming N-alpha-acetyl-L-seryl-[protein].
• This activity belongs to the molecular_function ontology and is synonymous with peptide-serine-alpha-N-acetyltransferase activity.
• N-terminal acetylation of serine residues is catalyzed by N-terminal acetyltransferases (NATs) such as RimL in E. coli and by eukaryotic NAT complexes.
• The reaction consumes acetyl-CoA and releases CoA and H+, and it is essential for protein stability, folding, and interactions.
• Dysregulation of N-terminal acetylation has been linked to cancer, immune signaling, and developmental disorders.
• CRISPR-based knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect the function of this activity in cells and organisms.
Description
Protein N-terminal-serine acetyltransferase activity (GO:1990189) is a molecular function that catalyzes the acetylation of the alpha-amino group of N-terminal serine residues in proteins. This modification, known as N-alpha-acetylation, is one of the most common co-translational modifications in eukaryotes and is also found in bacteria. The reaction uses acetyl-CoA as the acetyl donor and produces CoA and a proton, resulting in an N-alpha-acetyl-L-seryl-[protein]. This activity is critical for protein maturation, stability, and function, and its dysregulation has been implicated in various diseases, including cancer and immune disorders. Researchers study this activity to understand protein homeostasis, signal transduction, and to engineer proteins with improved properties for therapeutic applications.
protein N-terminal-serine acetyltransferase activity At A Glance
| GO ID | GO:1990189 |
|---|---|
| GO term | protein N-terminal-serine acetyltransferase activity |
| Ontology | molecular_function |
| Synonym | peptide-serine-alpha-N-acetyltransferase activity |
| Definition | Catalysis of the reaction: acetyl-CoA + N-terminal L-seryl-[protein] = CoA + H+ + N-terminal Nalpha-acetyl-L-seryl-[protein]. |
| Major function | Catalyzes N-terminal acetylation of serine residues in proteins, affecting protein stability, localization, and interactions. |
| Cofactor | Acetyl-CoA |
| Substrate | N-terminal L-seryl-[protein] |
| Product | N-terminal Nalpha-acetyl-L-seryl-[protein], CoA, H+ |
What Is GO:1990189?
According to the Gene Ontology, GO:1990189 is defined as the catalysis of the reaction: acetyl-CoA + N-terminal L-seryl-[protein] = CoA + H+ + N-terminal Nalpha-acetyl-L-seryl-[protein]. In simpler terms, it is an enzyme activity that attaches an acetyl group to the very first amino acid (serine) at the beginning of a protein chain. This modification is irreversible and occurs on the N-terminal alpha-amino group, distinguishing it from lysine acetylation. The activity is synonymous with peptide-serine-alpha-N-acetyltransferase activity and is classified under the molecular_function aspect of the ontology.
Why Is protein N-terminal-serine acetyltransferase activity Important in Cell Biology?
Protein N-terminal-serine acetyltransferase activity is fundamental to proteome regulation because N-terminal acetylation influences protein half-life, subcellular targeting, and complex formation. In eukaryotes, this modification is essential for viability, and its perturbation leads to defects in development, immune signaling, and stress responses. In biotechnology, harnessing this activity enables the production of correctly acetylated therapeutic proteins, such as thymosin β4 and thymosin α1, in bacterial expression systems. Thus, understanding GO:1990189 has broad implications for basic biology, disease mechanisms, and biopharmaceutical manufacturing.
• Regulates protein stability and degradation by affecting the N-end rule pathway.
• Modulates protein-protein interactions and subcellular localization.
• Essential for immune signaling, as seen in NF-kappaB regulation.
• Involved in cancer progression through altered acetylation of oncoproteins and tumor suppressors.
• Enables efficient biosynthesis of acetylated therapeutic peptides in E. coli.
• Plays a role in bacterial physiology and host-pathogen interactions.
• Provides a target for engineering proteins with enhanced stability and activity.
• Dysregulation is associated with developmental disorders and neurodegeneration.
• Serves as a model for studying enzyme-substrate specificity and catalysis.
• Facilitates the production of recombinant proteins with authentic N-termini for research and therapy.
What Happens During protein N-terminal-serine acetyltransferase activity?
Substrate Recognition and Binding
In simple terms: The enzyme first grabs the protein that needs to be modified.
The acetyltransferase recognizes the N-terminal serine residue of a target protein, often in a sequence-specific context. For example, E. coli RimL displays specificity for N-terminal serine or alanine residues, and its activity can be studied in vitro using bacterially expressed parvalbumins as substrates. The enzyme binds the substrate through a dedicated peptide-binding groove, positioning the alpha-amino group for catalysis.
Acetyl Group Transfer
In simple terms: The enzyme takes an acetyl group from acetyl-CoA and attaches it to the protein's start.
In the catalytic step, acetyl-CoA donates its acetyl group to the N-terminal alpha-amino group of the serine residue, forming an N-alpha-acetyl-L-seryl-[protein]. This reaction releases CoA and a proton. The mechanism likely involves a general acid-base catalysis, as suggested by studies on rat liver polysome N-alpha-acetyltransferase, which showed strict substrate specificity for N-terminal serine. The activity is essential for the maturation of many proteins, including thymosin β4 and thymosin α1 when produced in E. coli.
Product Release and Protein Fate
In simple terms: After acetylation, the protein is released and can go do its job.
Once acetylated, the protein may undergo folding, assembly into complexes, or targeting to specific cellular locations. N-terminal acetylation can protect proteins from degradation or, conversely, serve as a degradation signal depending on the context. For instance, acetylation of the Drosophila NF-kappaB factor Relish is mediated by a caspase and affects immune signaling. The acetylated product is functionally distinct from its unacetylated counterpart, influencing pathways such as NF-kappaB activation.
Key Genes Involved in GO:1990189 protein N-terminal-serine acetyltransferase activity
The following genes and proteins are directly or indirectly associated with protein N-terminal-serine acetyltransferase activity, based on experimental evidence from the cited literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| RimL | N-terminal acetyltransferase in E. coli | Model enzyme for studying substrate specificity and catalysis |
| NAA10 | Catalytic subunit of NatA complex | Major eukaryotic NAT; acetylates serine N-termini; linked to cancer and development |
| NAA15 | Auxiliary subunit of NatA | Regulates NatA activity and substrate selection |
| NAA20 | Catalytic subunit of NatB | Acetylates N-terminal methionine-aspartate/glutamate sequences |
| NAA25 | Auxiliary subunit of NatB | Modulates NatB function |
| NAA30 | Catalytic subunit of NatC | Acetylates N-terminal methionine-isoleucine/leucine sequences |
| NAA35 | Auxiliary subunit of NatC | Required for NatC stability |
| NAA50 | Catalytic subunit of NatE | Acetylates N-terminal methionine-lysine sequences |
| HBO1 | Histone acetyltransferase | Inhibits NF-kappaB activity by coactivator sequestration |
| Relish | Drosophila NF-kappaB factor | Caspase-mediated processing affects immune signaling |
| Thymosin β4 | Actin-sequestering peptide | N-terminal acetylation enhances stability and function |
| Thymosin α1 | Immunomodulatory peptide | N-terminal acetylation required for activity |
| Parvalbumin | Calcium-binding protein | Used as substrate to assay N-terminal acetylation |
| Acetyl-CoA | Acetyl group donor | Central metabolite for acetylation reactions |
| CoA | Product of acetyl transfer | Byproduct of the reaction |
| NAT complexes | Multi-subunit enzymes | Mediate N-terminal acetylation in eukaryotes |
How Is protein N-terminal-serine acetyltransferase activity Regulated?
The activity of protein N-terminal-serine acetyltransferases is regulated at multiple levels. In eukaryotes, the expression and assembly of NAT complexes are controlled by transcriptional and post-translational mechanisms. For example, the catalytic subunit NAA10 can be regulated by phosphorylation, and its activity is influenced by the availability of acetyl-CoA, which reflects cellular metabolic status. In bacteria, RimL activity may be modulated by growth conditions and substrate availability. Additionally, the activity can be inhibited by feedback from acetylated products or by interaction with regulatory proteins. The NF-kappaB pathway, which is affected by N-terminal acetylation, is subject to complex regulation involving caspases and acetyltransferases.
protein N-terminal-serine acetyltransferase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| NAA10 | Ogden syndrome; cancer | Knockout and point-mutation cell lines; patient-derived iPSCs |
| NAA15 | Developmental delay; cancer | Knockout zebrafish; mouse models |
| HBO1 | Inflammation; cancer | Knockout mice; NF-kappaB reporter assays |
| Relish | Immune signaling (Drosophila) | RNAi knockdown; caspase mutants |
| Thymosin β4 | Wound healing; cancer | Overexpression in E. coli for therapeutic production |
Cancer
Dysregulation of N-terminal acetylation has been observed in various cancers. For instance, NAA10 (also known as ARD1) is overexpressed in some tumors and contributes to cell proliferation and metastasis. The activity of N-terminal acetyltransferases can affect the stability of oncoproteins and tumor suppressors, thereby influencing cancer progression. Targeting these enzymes is being explored as a therapeutic strategy.
Immune Disorders
N-terminal acetylation plays a role in immune signaling. The Drosophila NF-kappaB factor Relish is processed by caspases, and its activity is modulated by acetylation. In mammals, the histone acetyltransferase HBO1 inhibits NF-kappaB activity by sequestering coactivators, highlighting the interplay between acetylation and inflammation. Aberrant acetylation may contribute to autoimmune diseases and chronic inflammation.
Developmental Disorders
Mutations in NAA10, the catalytic subunit of NatA, cause Ogden syndrome, a rare X-linked developmental disorder characterized by intellectual disability, cardiac arrhythmia, and facial dysmorphism. This underscores the critical role of N-terminal serine acetylation in human development.
From protein N-terminal-serine acetyltransferase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does loss of NAA10 affect cell viability? | CRISPR knockout of NAA10 in HeLa or HEK293 cells |
| How does a specific NAA10 mutation alter substrate specificity? | Point mutation knock-in of mutant NAA10 |
| Can N-terminal acetylation be tracked in live cells? | Knock-in of fluorescent tag at NAA10 locus |
| Does overexpression of RimL increase acetylation of recombinant proteins? | Overexpression of RimL in E. coli |
| What is the role of NAA15 in NatA complex assembly? | Knockout of NAA15 followed by proteomics |
| Does HBO1 regulate NF-kappaB via acetylation? | Knockout of HBO1 and NF-kappaB reporter assays |
How to Study the protein N-terminal-serine acetyltransferase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| In vitro acetyltransferase assay | Enzyme activity using peptide substrates | Characterizing substrate specificity of RimL |
| Mass spectrometry | N-terminal acetylation status and stoichiometry | Global acetylome profiling |
| CRISPR knockout | Loss-of-function phenotypes | Studying essentiality of NAA10 |
| CRISPR knock-in | Tagged or mutant protein expression | Live-cell imaging of NAT localization |
| Ribo-seq | Translation efficiency and ribosome occupancy | Assessing co-translational acetylation |
| RNA-seq | Transcriptional changes upon NAT perturbation | Identifying downstream pathways |
| Co-immunoprecipitation | Protein-protein interactions | Mapping NAT complex composition |
| Structural biology | 3D structure of enzyme-substrate complexes | Rational drug design |
In Vitro Acetyltransferase Assays
Recombinant enzymes and substrate peptides can be used to measure acetyltransferase activity. For example, the activity of E. coli RimL was studied using synthetic peptides and bacterially expressed parvalbumins. These assays typically monitor the transfer of radiolabeled or fluorescent acetyl groups from acetyl-CoA to the substrate.
Mass Spectrometry-Based Proteomics
Mass spectrometry can identify N-terminally acetylated peptides and quantify acetylation stoichiometry. This approach has been used to characterize the N-terminal acetylome and to validate substrates of specific NATs. It is particularly useful for studying the effects of knockout or overexpression of NAT subunits.
CRISPR-Cas9 Genome Editing
CRISPR-Cas9 allows the generation of knockout, point mutation, knock-in, and overexpression cell lines to study the function of N-terminal acetyltransferases. For instance, knocking out NAA10 can reveal its essential roles in cell proliferation and survival. These models are invaluable for linking genotype to phenotype.
Structural Biology and Modeling
X-ray crystallography and cryo-EM can provide insights into the catalytic mechanism and substrate binding of N-terminal acetyltransferases. Structural studies of RimL and NatA have revealed key residues involved in acetyl-CoA binding and catalysis.
How CRISPR Can Be Used to Study GO:1990189 protein N-terminal-serine acetyltransferase activity
Knockout
CRISPR knockout of genes encoding N-terminal acetyltransferases, such as NAA10 or RimL, can abolish the activity and reveal its cellular functions. For example, knocking out NAA10 in human cells leads to defects in proliferation and increased apoptosis, highlighting its essential role. In bacteria, rimL knockout reduces acetylation of specific proteins and affects stress responses.
Point Mutation
Introducing point mutations in the catalytic domain of N-terminal acetyltransferases can dissect the contribution of individual residues to catalysis and substrate binding. For instance, mutating the catalytic glutamate of RimL abolishes its activity, confirming its role in acetyl transfer. Such models are useful for understanding disease-associated mutations, like those in NAA10 causing Ogden syndrome.
Knock-in
Knock-in of epitope tags or fluorescent proteins at the endogenous locus allows real-time tracking of N-terminal acetyltransferase expression and localization. This approach can also be used to introduce disease-relevant mutations or to create conditional alleles. For example, knocking in a FLAG tag at the NAA10 locus enables immunoprecipitation and proteomic analysis of the NatA complex.
Overexpression
Overexpression of N-terminal acetyltransferases, such as RimL in E. coli, can enhance the production of N-terminally acetylated recombinant proteins, including therapeutic peptides like thymosin β4 and thymosin α1. This strategy is widely used in biotechnology to improve protein stability and activity.
How EDITGENE Supports protein N-terminal-serine acetyltransferase activity Research
Researchers studying protein N-terminal-serine acetyltransferase activity-related genes often need to determine whether a candidate gene is causally involved in a specific cellular process or disease. EDITGENE provides a comprehensive suite of CRISPR-based services to accelerate this discovery, from gene knockout to precise point mutations and knock-in models.
Contact EDITGENE today to design your custom CRISPR model for protein N-terminal-serine acetyltransferase activity research.
Frequently Asked Questions About protein N-terminal-serine acetyltransferase activity
What is protein N-terminal-serine acetyltransferase activity?
It is an enzyme activity that adds an acetyl group to the N-terminal serine residue of a protein, as defined by GO:1990189. This modification affects protein stability and function.
What genes are involved in protein N-terminal-serine acetyltransferase activity?
Key genes include NAA10, NAA15, NAA20, NAA25, NAA30, NAA35, NAA50, and bacterial RimL. These encode subunits of N-terminal acetyltransferase complexes.
What is the GO ID for protein N-terminal-serine acetyltransferase activity?
The Gene Ontology ID is GO:1990189.
What is the synonym for GO:1990189?
The synonym is peptide-serine-alpha-N-acetyltransferase activity.
How does N-terminal acetylation affect protein function?
It can influence protein stability, localization, interactions, and degradation, often by affecting the N-end rule pathway.
Which diseases are linked to N-terminal acetylation?
Dysregulation is associated with cancer, immune disorders, and developmental syndromes like Ogden syndrome.
Can N-terminal acetylation be studied in bacteria?
Yes, E. coli RimL is a model enzyme for studying N-terminal acetylation, and it can be used to produce acetylated recombinant proteins.
What methods are used to measure N-terminal acetyltransferase activity?
Common methods include in vitro assays with acetyl-CoA, mass spectrometry, and CRISPR-based genetic screens.
How can CRISPR help study GO:1990189?
CRISPR knockout, knock-in, and point mutation models allow researchers to dissect the function of N-terminal acetyltransferases in cells and organisms.
What is the role of acetyl-CoA in this activity?
Acetyl-CoA serves as the acetyl group donor in the reaction catalyzed by N-terminal acetyltransferases.
Conclusion
Protein N-terminal-serine acetyltransferase activity (GO:1990189) is a fundamental enzymatic function that regulates protein fate and cellular signaling. Its importance spans from bacterial physiology to human disease, and it is a key target for biotechnology and therapeutic development. By leveraging CRISPR-based models and advanced proteomics, researchers can uncover new insights into this modification and its roles in health and disease.
References
- 1. Lapteva YS et al.. 2021. In Vitro N-Terminal Acetylation of Bacterially Expressed Parvalbumins by N-Terminal Acetyltransferases from Escherichia coli.. Appl Biochem Biotechnol 193(5):1365-1378 PMID: 32394317
- 2. Yu R et al.. 2018. Highly effective biosynthesis of N-acetylated human thymosin β4 (Tβ4) in Escherichia coli.. Artif Cells Nanomed Biotechnol 46(sup3):S95-S104 PMID: 29989423
- 3. Ren Y et al.. 2011. Production of Nα-acetylated thymosin α1 in Escherichia coli.. Microb Cell Fact 10:26 PMID: 21513520
- 4. Miao L et al.. 2007. Studies of the in vitro Nalpha-acetyltransferase activities of E. coli RimL protein.. Biochem Biophys Res Commun 357(3):641-7 PMID: 17445774
- 5. Stoven S et al.. 2003. Caspase-mediated processing of the Drosophila NF-kappaB factor Relish.. Proc Natl Acad Sci U S A 100(10):5991-6 PMID: 12732719
- 6. Yamada R et al.. 1991. Rat liver polysome N alpha-acetyltransferase: substrate specificity.. Biochemistry 30(4):1017-21 PMID: 1846556
- 7. Contzler R et al.. 2006. Histone acetyltransferase HBO1 inhibits NF-kappaB activity by coactivator sequestration.. Biochem Biophys Res Commun 350(1):208-13 PMID: 16997280
