Single-step purification of recombinant Gaussia luciferase from serum-containing culture medium of mammalian cells

- The histidine-tagged Gaussia luciferase (GLase-His) is secreted from mammalian cells.
- A CHO-K1/dhfr- cell line stably expressing GLase-His was established.
- GLase-His was purified from the serum-containing medium in a single-step Ni-chelate column.
- Non-ionic detergents and NaCl stimulated luminescence activity of purified GLase-His.
- Purified GLase-His showed similar luminescence properties to GLase from E. coli cells.

A dihydrofolate reductase-deficient Chinese hamster ovary (CHO-K1/dhfr-) cell line stably expressing Gaussia luciferase with a histidine-tag sequence at the carboxyl terminus (GLase-His) was established. Recombinant GLase-His was purified from serum-containing culture medium by single-step Ni-chelate column chromatography in the presence of 2 M NaCl and 0.01% Tween 20. The protein yield of GLase-His with over 95% purity was 0.5 mg from 0.9 L of the cultured medium. The enzymatic properties of purified GLase-His were characterized. Interestingly, non-ionic detergent Tween 20 stabilized and stimulated GLase-His activity and its luminescence activity was stimulated 2-fold by the synergistic effect of 0.01% Tween 20 and 150 mM NaCl.