Choose the correct statements about the recombinant expression of prot...
Poly His can effectively bind with Ni column and helps in purification, while GFP or green fluorescent markers help in determining expression. Smallpox and adenovirus are commonly used for cloning and expression but, after removing the genes for pathogenicity.
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Choose the correct statements about the recombinant expression of prot...
Introduction:
Recombinant expression of proteins is a widely used technique in molecular biology to produce large quantities of specific proteins for various purposes. It involves the insertion of a gene encoding the protein of interest into a host organism, such as bacteria, yeast, or mammalian cells, which then produce the protein.
Statement a) A human protein can never be expressed in a bacterial cell:
This statement is incorrect. While it is true that bacterial cells lack the necessary machinery to correctly fold and modify certain human proteins, many human proteins can be successfully expressed in bacterial cells. Bacterial expression systems offer several advantages, such as ease of use, cost-effectiveness, and high protein yields. To overcome the limitations of bacterial cells, strategies like codon optimization, fusion with solubility-enhancing tags, and co-expression with chaperones can be employed.
Statement b) A marker gene such as GFP is often used to confirm the expression:
This statement is correct. Marker genes, such as Green Fluorescent Protein (GFP), are frequently used to confirm the expression of recombinant proteins. GFP is a protein that emits green fluorescence when exposed to specific wavelengths of light. By fusing the gene encoding the protein of interest with the GFP gene, the expression and localization of the recombinant protein can be visualized directly under a fluorescence microscope or detected using fluorescence-based assays.
Statement c) A purification tag is often made up of poly His coding sequence in recombinant construct:
This statement is correct. A purification tag is a short peptide sequence that is fused to the protein of interest to facilitate its purification from complex mixtures. One commonly used purification tag is the polyhistidine (poly His) tag, which consists of several consecutive histidine residues. The poly His tag allows purification of the recombinant protein using immobilized metal ion affinity chromatography (IMAC), as histidine residues have a strong affinity for metal ions such as nickel or cobalt. This tag can be added to either the N- or C-terminus of the protein of interest, enabling its efficient purification.
Statement d) Disease causing viruses like smallpox and adenovirus cannot be used as cloning vectors:
This statement is not given in the options.