Protein Secretion and Expression Hosts Flashcards
Recombinant Proteins
The protein expressed from an rDNA gene
Functions of recombinant proteins (not monoclonal antibodies)
-Replacements for missing/dead proteins
-Increasing amount of proteins already present
-Inhibiting infectious agents (bacteria/viruses)
-Carrying other molecules (mostly in development)
These categories are not mutually exclusive
What does cloning a gene onto a high-copy-number plasmid do?
Results in a higher yield of a gene product, but they are often unstable
Protein fusion
Joining of coding sequences of two proteins together in a frame
What does protein fusion address?
Stability and purification
Protein fusion vector
a plasmid that allows the gene of interest to be fused to the gene for a suitable carrier protein
Vector
A tool used for introducing a foreign gene into a cell/organism such that it can replicate and propagate
(a broad term similar to how we use ‘gene’)
Glycosylation
When short chains of sugar derivatives are added to proteins after translation
What glycosyl groups do Eukaryotes typically have
N-linked glycosyl groups
What does altering the glycosylation pattern on a protein do?
Results in useful alterations in protein behavior
Where is usually best to express eukaryotic proteins?
In eukaryotic cells
What are the advantages of expressing proteins in EUKARYOTIC cells over prokaryotic cells?
-Prokaryotes may not provide the needed disulfide bonds
-Prokaryotes do not glycosylate
-Prokaryotes do not fold mammalian proteins properly
What are the advantages of expressing proteins in PROKARYOTIC cells over eukaryotic cells?
-Eukaryotes are more difficult
-Eukaryotes are more expense
What can occur if a eukaryotic protein is made by an unfit bacterial cell
The protein will become unstable or inactive (especially if post-translational modification is needed)
What are two ways we can manufacture large quantities of protein products
- Isolate/purify from the natural host
- Overexpress as a recombinant protein
