Avidin is a promising tag for fusion proteins produced in baculovirus-infected insect cells

The baculovirus expression vector system (BEVS) has become one of the most versatile and powerful eukaryotic systems for recombinant protein expressio n. We have constructed a novel baculovirus transfer vector (pbacAVs+C) whic h allows for the efficient production, detection, and single-step purificat ion of the desired molecule as a secretion-compatible avidin fusion protein in insect cells. It also enables fast construction of the baculoviruses by site-specific transposition in Escherichia coli. To demonstrate the power of this vector, we report here on the production of immunologically intact hevein, a major cysteine-rich latex allergen, as avidin fusion protein. Our results indicate that avidin is a stable and versatile tag in the BEVS. It retains its extraordinarily high biotin-binding activity and also enables independent folding of the fusion partner. The versatility with which avidi n fusion proteins can be detected, purified, and immobilized is the basis f or the use of our system as a useful alternative in eukaryotic fusion prote in production. (C) 1999 Academic Press.