Expression and purification of short hydrophobic elastin-like polypeptides with maltose-binding protein as a solubility tag
Résumé
Elastin-like polypeptides (ELPs) are biodegradable polymers with interesting physico-chemical properties for biomedical and biotechnological applications. The recombinant expression of hydrophobic elastin-like polypeptides is often difficult because they possess low transition temperatures, and therefore form aggregates at sub-ambient temperatures. To circumvent this difficulty, we expressed in Escherichia coli three hydrophobic ELPs (VPGIG)(n) with variable lengths (n = 20, 40, and 60) in fusion with the maltose-binding protein (MBP). Fusion proteins were soluble and yields of purified MBP-ELP ranged between 66 and 127 mg/L culture. After digestion of the fusion proteins by enterokinase, the ELF moiety was purified by using inverse transition cycling. The purified fraction containing ELP40 was slightly contaminated by traces of undigested fusion protein. Purification of ELP60 was impaired because of co-purification of the MBP tag during inverse transition cycling. ELP20 was successfully purified to homogeneity, as assessed by gel electrophoresis and mass spectrometry analyses. The transition temperature of ELP20 was measured at 15.4 degrees C in low salt buffer. In conclusion, this method can be used to produce hydrophobic ELF of low molecular mass
Mots clés
Elastin-like polypeptides
Precision polymers
Recombinant expression
Maltose-binding protein transition temperature
Mass spectrometry
INVERSE TEMPERATURE TRANSITION
RECURSIVE DIRECTIONAL LIGATION
ESCHERICHIA-COLI
RECOMBINANT PROTEINS
MOLECULAR-WEIGHT
PHASE-TRANSITION
AQUEOUS-SOLUTION
FREE-ENERGY
E. COLI
MODEL