Protein expression in Escherichia coli may result in the recombinant protein being expressed as insoluble inclusion bodies. In addition, proteins purified from E. coli contain endotoxins which need to be removed for in vivo applications.
There are ~2 x 106 LPS molecules per cell, accounting for 30% of total outer membrane gross weight. In mammalian cell culture, LPS contamination triggers secretion of pro-inflammatory cytokines, poor cell growth, reduced DNA transfection efficiency, problematic differentiation, cell death, and compromised experimental results. In humans, LPS activates the immune system, resulting in endotoxic shock or even death.
Creative BioMart has endotoxin-free Expression System to engineer E. coli that are viable and robust in research and industrial culture conditions and yet devoid of the lipid A component of endotoxin. Due to a suppressor mutation the organism produces a substitute, non-toxic molecule to populate the outer membrane. Additional mutations prevent reversion to the lipid A-producing phenotype.
For the most part, production strains using the endotoxin-free Expression System are identical to the wild-type counterparts except that they lack endotoxic activity. These strains exhibit normal growth rates, reach high ODs, and express with similar yields a wide variety of proteins and oligonucleotides that typically express in E. coli.
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