Your Outsourcing Partner for Protein Research and Production Services

To meet the needs of our clients, Exon BioSystems provides protein characterization of our expressed protein to insure the quality of recombinant protein.

Recombinant Protein Expression

Exon BioSystems is a protein contract research and production services company specializing in recombinant protein expression, protein purification, and protein characterization.

Antibody Engineering

Additional areas of expertise include assay development of G-protein coupled receptor, recombinant vaccine development and recombinant antibody production.

Biologics

Exon BioSystems is a protein contract research and production services company specializing in recombinant protein expression, protein purification, and protein characterization.

Protein Expression Services

Promoters

Overview of E. coli promoter systems useful for heterologous protein production
Promoters expression Level (inductor) Key features
lac promoter Low level up to middle (IPTG) Weak, regulated suitable for gene products at very low intracellular level.
Comparatively expensive induction.
trc and tac promoter Moderately high (IPTG) High-level, but lower than T7 system. Regulated expression still possible.
Comparatively expensive induction. High basal level.
T7 RNA polymerase Very high (IPTG) Utilizes T7 RNA polymerase. High-level inducible over expression.
T7lac system for tight control of induction needed for more toxic clones.
Quite expensive induction. Basal level depends on strain used (pLys).
Phage promoter pL Moderately high (temperature shift) Temperature-sensitive host required. Less likelihood of "leaky" un-induced expression. Basal level; high basal level by temperatures below 30°C. No inducer.
tetA promoter/operator Variable from middle to high level (anhydrotetracyclin) Tight regulation. Independent of metabolic state. Independent of E. coli strain.
Relatively inexpensive inducer. Low basal level.
PPBAD promoter Variable from low to high level
(L-arabinose)
Can fine-tune expression levels in a dose-dependent manner. Tight regulation possible. Low basal level. Inexpensive inducer.
PBAD promoter Variable from low to high level Tight regulation. Low basal activity. Relatively expensive inducer.

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