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Expression and purification in baculovirus system
Insect cells Sf9, Sf21 or Hi5
Protein production system in baculovirus (Insect cells)
Baculoviruses are a family of viruses featured by a rod-shaped appearance (in Latin Baculum means stick), the Baculoviridae. They are characterized by two sub-families: Eubaculovirinae with Nucleopolyhedrovirus (NPV) and Granulovirus (GV), the Nudibaculoviridae. These viruses can infect mostly moth species but they have also been found infecting sawflies, mosquitoes and even crustaceans.
Today, no known baculovirus is capable of infecting mammals or other vertebrates. The baculovirus genome consists of a double-stranded circular DNA whose size is between 80 and 180 kbp, which makes it a large virus.
Baculoviruses are used in biotechnology for the production of recombinant proteins since 1983. These viruses enable to introduce the gene encoding the protein to be produced in cultured insect cells, including cells of Spodoptera frugiperda (Sf9 and Sf21) and Trichoplusia ni (Hi5)
The cDNA of the protein of interest is integrated into the genome of the virus by replacing the gene encoding the fibril structure protein p10, which is not useful for the virus in cell culture. The protein interferon beta is an example of a protein produced in baculovirus.
Proteogenix – Recombinant protein expression platform in baculovirus
Proteogenix offers services of protein expression in baculovirus and insect cells Sf9, Sf21 or Hi5. The advantage of this system (Baculovirus Expression Vector System : BEVS) is that after a production and purification you get a functional recombinant protein with correct post translational modifications (PTM): disulfide bonds formation, glycolsylation (N-and O- ), signal peptide cleavage, no N-terminal methionine, myristylations, acetylations, phosphorylations, ubiquitinations, glycolipid anchors, multiple splicing, heterodimeric assemblies, pro-peptides maturation, etc. These modifications guarantee a good biological activity.
Expression system in baculovirus and post translational modifications (PTM)
Some post-translational modifications (PTM) such as myristylations, acetylations, phosphorylations, ubiquitinations and glycolsylations (O-and N-) are correctly performed only in complex eukaryotic organisms. Baculovirus system was not perfect until very recently for the production of mammalian proteins, in the sense that some types of insect cells were not able to make N-glycosylation entirely (It only reached the 3 mannose molecules), although they are at the right place. However, Sf9 cells for instance, can now produce N-glycosylation similar to those produced in mammalian cells (the only difference being that the sialic acid is modified by a hydroxyl).
Insect cells expression system advantages
The amounts of protein obtained from our baculovirus system are generally greater than with other advanced eukaryotic systems and especially for intracellular proteins. Other advantages of the baculovirus / insect cell (insect larvae) system are genomic stability and the safety aspect in that cells are grown without animal proteins.
More information about the protocol of protein expression in Baculovirus here.