Expression and purification of a recombinant adenovirus fiber knob in a baculovirus system.

OBJECTIVES

To construct a recombinant baculovirus expressing the fiber knob domain of human adenovirus type 2 modified by the insertion of a foreign peptide, purify this protein after its production in insect cells, and to test its properties.

METHODS

Recombinant baculoviruses expressing the fiber knob were produced in Sf9 cells. The recombinant fiber knob was recovered from culture supernatants of infected cells and purified by a combination of Ni-NTA and ion-exchange chromatography.

RESULTS

Fiber knob was recovered from the culture media as a soluble protein. In the system used, the fiber knob is expressed fused with the V5 epitope and a histidine tag, which allowed purification by Ni-NTA chromatography. The protein was further purified by ion-exchange chromatography. We show that the recombinant fiber knob produced, with 31 extra amino acids in the C-terminus, can oligomerize and bind to the adenovirus receptor CAR, as it can block the infection of a recombinant type 5 adenovirus.

CONCLUSIONS

The modified form of the fiber knob, produced in insect cells and purified by Ni-NTA and ion-exchange chromatography, retains the properties of oligomerization and binding to the fiber natural receptor, CAR. This construct has the potential to be a new adjuvant.