Recombinant Proteins

Indian Institute of Science (IISc), Bengaluru have formulated method for mass-producing recombinant proteins.

Definition of Recombinant Proteins: Recombinant proteins are artificial proteins produced by genetic engineering techniques. The process involves inserting a specific gene (usually from one organism) into a host organism (typically bacteria or yeast), which then expresses the protein.

Importance in Biotechnology: This process is fundamental to genetic engineering and biotechnology. It allows scientists to produce large quantities of specific proteins that may be difficult to obtain from natural sources.

Historical Milestone: The first recombinant protein produced was human insulin, which revolutionized diabetes treatment. This was a major breakthrough in the field of biotechnology and medicine.

Recent Development: The Indian Institute of Science (IISc) in Bengaluru has formulated a method for mass-producing recombinant proteins. This is a significant advancement as it could potentially make the production of these proteins more efficient and cost-effective.

Applications:

 Recombinant proteins have numerous applications in various fields, including:

Medicine: Production of therapeutic proteins, vaccines, and diagnostic tools

Research: Study of protein structure and function

Industry: Production of enzymes for various industrial processes

Agriculture: Development of pest-resistant crops or plants with enhanced nutritional value

Process: The process involves creating new genetic sequences by combining genetic material from different sources. This allows for the production of proteins that may not exist in nature or to produce natural proteins in larger quantities than would be possible through traditional extraction methods.

Advantages:

Allows for large-scale production of specific proteins

Can produce proteins that are difficult or impossible to obtain from natural sources

Enables modification of proteins for enhanced function or stability

Reduces the risk of contamination with unwanted substances that might be present in natural sources

Mechanisms of Recombinant Protein Technology

1. Gene Isolation: This step involves identifying and extracting the specific gene that codes for the desired protein. Techniques used include:

• PCR (Polymerase Chain Reaction) to amplify the gene of interest
• Restriction enzyme digestion to cut out the gene from the source DNA
• cDNA synthesis from mRNA if working with eukaryotic genes

2. Vector Construction: Once isolated, the gene is inserted into a vector, which is typically a plasmid for bacterial hosts or a viral vector for mammalian cells. This process involves:

• Choosing an appropriate vector based on the host organism and expression requirements
• Using restriction enzymes and DNA ligase to cut the vector and insert the gene
• Adding promoter sequences to control gene expression
• Incorporating selectable markers (e.g., antibiotic resistance genes) to identify transformed cells

3. Transformation: The recombinant vector is introduced into host cells. Methods vary depending on the host:

• For bacteria: heat shock or electroporation
• For yeast: lithium acetate-mediated transformation
• For mammalian cells: lipofection, electroporation, or viral transduction

4. Protein Expression: The host cell's machinery is used to produce the recombinant protein. This step involves:

• Optimizing growth conditions (temperature, pH, nutrients) for the host cell
• Inducing protein expression (e.g., using IPTG for lac operon-based systems)
• Monitoring protein production levels
• Addressing issues like protein folding or post-translational modifications

5. Purification: The final step involves extracting and purifying the recombinant protein. This typically includes:

• Cell lysis to release the protein (if not secreted)
• Initial separation using centrifugation or filtration
• Chromatography techniques (e.g., affinity, ion exchange, size exclusion)
• Verifying protein purity using techniques like SDS-PAGE or mass spectrometry