GO:0042026 protein refolding: Mechanisms, Genes, Functions and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0042026 protein refolding describes the biological process by which a polypeptide chain acquires its native three-dimensional structure, either spontaneously or with the assistance of folding helpers.
• In biotechnology, protein refolding is essential for recovering bioactive proteins from inclusion bodies produced in Escherichia coli and other expression systems.
• Chemical refolding additives, such as osmolytes, detergents, and chaperone-like molecules, are widely used to suppress aggregation and improve refolding yields.
• Chromatographic and non-chromatographic strategies enable scalable refolding of recombinant proteins for industrial and therapeutic applications.
• Advanced technologies such as flash-change reaction conditions and UCST-type ureido polymers provide spatiotemporal control over protein refolding.
• Online monitoring by intrinsic fluorescence allows real-time tracking of refolding during inclusion body processing, improving process analytical technology.
Description
Protein refolding (GO:0042026) is the biological process through which a denatured or misfolded polypeptide chain transitions to its functional, native three-dimensional conformation. This process is fundamental to cellular proteostasis and is also a critical step in the industrial production of recombinant proteins, where high-level expression often leads to the formation of insoluble inclusion bodies that must be solubilized and refolded. Understanding the molecular mechanisms and optimizing refolding conditions are therefore of great interest to both basic researchers and biotechnologists. In the laboratory, protein refolding is studied using a variety of chemical and physical strategies, including the use of additives, chromatographic procedures, and advanced polymer-based systems. Recent methodological advances have enabled real-time monitoring of refolding, providing deeper insights into folding kinetics and aggregation pathways. This article summarizes the current knowledge on protein refolding, highlighting key genes, research methods, and the relevance of this process to human disease and biotechnology.
protein refolding At A Glance
| GO ID | GO:0042026 |
|---|---|
| GO term | protein refolding |
| Ontology | biological_process |
| Synonym | None |
| Major function | Acquisition of native protein conformation from a denatured state |
| Related processes | Protein folding, chaperone-mediated folding, inclusion body processing |
| Industrial relevance | Recovery of bioactive recombinant proteins from inclusion bodies |
| Key additives | Osmolytes, detergents, polymers, chaperone-like molecules |
What Is GO:0042026?
Protein refolding (GO:0042026) is defined as the process by which a protein adopts its correct three-dimensional structure from a denatured or unfolded state, either spontaneously or with the assistance of folding aids. In the context of recombinant protein production, it refers to the in vitro recovery of bioactive proteins from inclusion bodies after solubilization.
Why Is protein refolding Important in Cell Biology?
Protein refolding is essential for both cellular function and biotechnology. In cells, failure to refold proteins correctly can lead to aggregation and disease. In industry, refolding is a bottleneck in the production of therapeutic proteins from inclusion bodies, and optimizing refolding conditions directly impacts yield and cost. Therefore, understanding and controlling protein refolding has broad implications for medicine and biomanufacturing.
• Enables recovery of bioactive recombinant proteins from inclusion bodies in E. coli and other hosts.
• Critical for producing therapeutic proteins, enzymes, and antibodies at industrial scale.
• Chemical additives can dramatically improve refolding yields by suppressing aggregation.
• Advanced polymer systems allow spatiotemporal control of refolding.
• Real-time monitoring of refolding enhances process analytical technology.
• Misfolding and aggregation are linked to neurodegenerative diseases and other proteinopathies.
• Refolding strategies are essential for structural and functional studies of proteins.
• Non-chromatographic methods provide cost-effective alternatives for large-scale refolding.
• Understanding refolding mechanisms informs the design of novel biotherapeutics.
• Refolding is a key step in the production of biosimilars and biobetters.
What Happens During protein refolding?
Solubilization of Inclusion Bodies
In simple terms: First, the clumped protein is dissolved using chemicals.
Inclusion bodies are solubilized using denaturants such as urea or guanidine hydrochloride, often with reducing agents to break disulfide bonds. Mild solubilization processes can preserve some native-like structure and improve refolding yields.
Removal of Denaturant and Initiation of Refolding
In simple terms: The denaturant is removed so the protein can start folding.
Refolding is initiated by removing or diluting the denaturant, typically through dialysis, dilution, or chromatographic methods. The choice of method affects aggregation and yield.
Role of Chemical Additives
In simple terms: Additives help the protein fold correctly and prevent clumping.
Chemical refolding additives, such as osmolytes, detergents, and polymers, suppress aggregation and stabilize folding intermediates. They are often used in combination to optimize refolding conditions.
Chromatographic Refolding
In simple terms: Columns can be used to refold proteins while separating them.
Chromatographic procedures, including size-exclusion, ion-exchange, and affinity chromatography, can refold proteins while removing denaturant and impurities. These methods offer better control and scalability.
Advanced Control and Monitoring
In simple terms: New technologies allow precise control and real-time tracking of refolding.
Flash-change reaction conditions and UCST-type ureido polymers enable spatiotemporal control of refolding. Online monitoring by intrinsic fluorescence provides real-time data on refolding progress.
Key Genes Involved in GO:0042026 protein refolding
The following genes and proteins are commonly studied in the context of protein refolding, including chaperones, foldases, and aggregation-prone targets.
| Gene | Major Role | Research Relevance |
|---|---|---|
| HSPA1A | Molecular chaperone Hsp70 | Assists protein refolding and prevents aggregation |
| HSPA8 | Hsc70 chaperone | Involved in chaperone-mediated refolding |
| HSPD1 | Hsp60 chaperonin | Facilitates folding of newly synthesized proteins |
| HSP90AA1 | Hsp90 chaperone | Stabilizes client proteins and aids refolding |
| DNAJB1 | Hsp40 co-chaperone | Stimulates Hsp70 ATPase activity |
| DNAK | Bacterial Hsp70 | Key chaperone in E. coli refolding |
| GROEL | Bacterial chaperonin | Assists folding in E. coli |
| PDIA1 | Protein disulfide isomerase | Catalyzes disulfide bond formation during refolding |
| PPIA | Peptidyl-prolyl isomerase | Accelerates proline isomerization |
| CLPB | Caseinolytic protease B | Disaggregase and refolding helper |
| HSPB1 | Small heat shock protein | Holds denatured proteins for refolding |
| BAG3 | Co-chaperone | Regulates chaperone-assisted refolding |
| STIP1 | Hsp70-Hsp90 organizing protein | Coordinates chaperone machinery |
| HSPA5 | BiP chaperone | ER refolding and quality control |
| CALR | Calreticulin | ER chaperone for glycoprotein folding |
| CANX | Calnexin | ER chaperone for glycoprotein folding |
| PDIA3 | ERp57 | Disulfide isomerase in ER |
| UGGT1 | UDP-glucose glycoprotein glucosyltransferase | ER quality control sensor |
How Is protein refolding Regulated?
Protein refolding is regulated at multiple levels. In cells, chaperone expression is controlled by heat shock transcription factors (HSFs) and the unfolded protein response (UPR). In vitro, refolding conditions such as pH, temperature, ionic strength, and the presence of additives critically influence the process. Advanced systems allow spatiotemporal regulation of refolding through stimuli-responsive polymers.
protein refolding and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| HSPA1A | Neurodegeneration | Knockout in neuronal cell lines |
| HSP90AA1 | Cancer | Point mutation to study ATPase activity |
| DNAJB1 | Protein aggregation | Overexpression in E. coli |
| PDIA1 | ER stress-related diseases | Knock-in of tagged version |
| CLPB | Protein misfolding | Knockout in mammalian cells |
Protein Misfolding Diseases
Defects in protein refolding can lead to aggregation and are associated with neurodegenerative diseases such as Alzheimer's and Parkinson's. Chaperone dysfunction contributes to these pathologies.
Cancer
Chaperones involved in refolding, such as Hsp90 and Hsp70, are often overexpressed in cancer and support tumor cell survival. Inhibitors of these chaperones are being explored as anticancer agents.
Biopharmaceutical Production
Inefficient refolding during manufacturing of therapeutic proteins can lead to low yields and immunogenicity. Optimized refolding processes are critical for producing safe and effective biologics.
From protein refolding-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does gene X assist protein refolding? | Knockout cell line |
| Does mutation Y affect chaperone activity? | Point mutation knock-in |
| Can tagged chaperone be tracked? | Knock-in of fluorescent tag |
| Does overexpression improve refolding yield? | Overexpression cell line |
| Which genes are essential for refolding? | CRISPR library screening |
| How does refolding change over time? | Live-cell imaging with tagged proteins |
How to Study the protein refolding Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Dilution refolding | Recovery of activity | Industrial protein production |
| Chromatographic refolding | Purity and activity | Lab-scale refolding |
| Intrinsic fluorescence | Conformational changes | Real-time monitoring |
| Flash-change | Kinetics of refolding | Spatiotemporal control |
| UCST polymer | Refolding yield | Smart refolding systems |
| CRISPR knockout | Gene function | Identifying essential genes |
| CRISPR library screening | High-throughput gene discovery | Novel refolding factors |
| Proteomics | Protein interactions | Chaperone networks |
In Vitro Refolding Assays
Common methods include dilution, dialysis, and chromatographic refolding, often monitored by spectroscopy or activity assays. Additives are screened to optimize conditions.
Advanced Monitoring Techniques
Intrinsic fluorescence and light scattering allow real-time monitoring of refolding and aggregation. Flash-change and polymer-based systems provide precise control.
Genetic and Genomic Approaches
CRISPR knockout, point mutation, and overexpression models are used to study gene function in refolding. CRISPR library screening can identify novel refolding factors.
Proteomics and Structural Biology
Mass spectrometry and NMR can characterize refolding intermediates and final conformations. These methods complement functional assays.
How CRISPR Can Be Used to Study GO:0042026 protein refolding
Knockout
CRISPR knockout of chaperone genes (e.g., HSPA1A) can reveal their essential role in protein refolding and cellular stress responses.
Point Mutation
Introducing point mutations in chaperone ATPase domains (e.g., HSP90AA1) allows dissection of catalytic mechanisms in refolding.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) into endogenous chaperone loci enables real-time imaging of refolding in live cells.
Overexpression
Overexpression of chaperones or foldases (e.g., PDIA1) can enhance refolding yields in recombinant protein production.
How EDITGENE Supports protein refolding Research
Researchers studying protein refolding-related genes often need to determine whether a candidate gene is causally involved in the process or merely correlated. EDITGENE provides a comprehensive suite of CRISPR services to enable precise genetic manipulation and functional validation.
Contact EDITGENE today to design your custom CRISPR model for protein refolding research.
Frequently Asked Questions About protein refolding
What is protein refolding (GO:0042026)?
Protein refolding is the biological process by which a denatured protein acquires its native three-dimensional structure, often assisted by chaperones or chemical additives.
What genes are involved in protein refolding?
Key genes include HSPA1A, HSP90AA1, DNAJB1, PDIA1, and bacterial chaperones like DNAK and GROEL.
Why is protein refolding important in biotechnology?
It enables recovery of bioactive recombinant proteins from inclusion bodies, which is critical for producing therapeutics and enzymes.
What are common additives used in protein refolding?
Osmolytes, detergents, and polymers are commonly used to suppress aggregation and improve refolding yields.
How can I study protein refolding in the lab?
Methods include dilution, dialysis, chromatographic refolding, and advanced monitoring by intrinsic fluorescence.
What is the role of chaperones in protein refolding?
Chaperones assist folding by preventing aggregation and facilitating conformational changes.
Can CRISPR be used to study protein refolding?
Yes, CRISPR knockout, point mutation, knock-in, and overexpression models are powerful tools to dissect gene function in refolding.
What diseases are linked to defective protein refolding?
Neurodegenerative diseases, cancer, and ER stress-related disorders are associated with impaired refolding.
What are advanced technologies for controlling refolding?
Flash-change reaction conditions and UCST-type ureido polymers allow spatiotemporal control of refolding.
How is refolding monitored in real time?
Intrinsic fluorescence and light scattering can track refolding and aggregation continuously.
Conclusion
Protein refolding (GO:0042026) is a fundamental biological process with wide-ranging implications for cellular health and biotechnological production. Advances in chemical additives, chromatographic methods, and smart polymer systems continue to improve refolding yields and control. CRISPR-based genetic models are invaluable for dissecting the molecular players involved. As the demand for therapeutic proteins grows, optimizing refolding processes remains a key challenge and opportunity for researchers and industry alike.
References
- 1. Singh A et al.. 2015. Protein recovery from inclusion bodies of Escherichia coli using mild solubilization process.. Microb Cell Fact 14:41 PMID: 25889252
- 2. Yamaguchi S et al.. 2013. Protein refolding using chemical refolding additives.. Biotechnol J 8(1):17-31 PMID: 22965925
- 3. Clark ED. 2001. Protein refolding for industrial processes.. Curr Opin Biotechnol 12(2):202-7 PMID: 11287238
- 4. Gautam S et al.. 2012. Non-chromatographic strategies for protein refolding.. Recent Pat Biotechnol 6(1):57-68 PMID: 22420882
- 5. Nakahara Y et al.. 2024. Spatiotemporal Control of Protein Refolding through Flash-Change Reaction Conditions.. Langmuir 40(16):8483-8492 PMID: 38618876
- 6. Tanaka Y et al.. 2022. Smart Protein Refolding System Based on UCST-Type Ureido Polymers.. Biomacromolecules 23(9):3860-3865 PMID: 36030420
- 7. Li M et al.. 2004. In vitro protein refolding by chromatographic procedures.. Protein Expr Purif 33(1):1-10 PMID: 14680955
- 8. Igwe CL et al.. 2024. Online monitoring of protein refolding in inclusion body processing using intrinsic fluorescence.. Anal Bioanal Chem 416(12):3019-3032 PMID: 38573344
