The recombinant bifunctional protein HELP-UnaG (HUG) is a fusion product of the Human Elastin-like Polypeptide (HELP) with the bilirubin-binding fluorescent protein UnaG. HUG is used for the fluorometric detection of bilirubin in serum and a variety of biological fluids and extracts. Here we describe a detailed method for the standardized production and purification of HUG from E. coli extracts on a laboratory scale. This method takes advantage of the HELP-specific thermoreactive behavior that enables the separation of HUG from complex E. coli extracts by repeated precipitation/re-dissolution steps at near physiological temperature.•The method is based on the inverse thermal transition process.•The "green" method is affordable for basic laboratories and can be easily transferred to new users.
Keywords: HUG; Human elastin-like fusion proteins; Inverse thermal transition; Lab-scale production of the recombinant fusion protein HUG; Protein purification method.
© 2024 The Author(s).