West Nile virus protease activity in detergent solutions and application for affinity tag removal.

Affinity tags are typically used to facilitate membrane protein purification. A protease needs to remain active in the presence of detergent to remove a fusion tag from a recombinant membrane protein. Our results show that the West Nile virus (WNV) protease activity was not affected while in the presence of a wide range of detergents. In a detergent solution, the WNV protease can remove the fusion tag from a recombinant protein containing KCNE3 and a WNV protease site. Therefore, the WNV protease may be useful as an alternative enzyme to remove affinity tags in protein purifications.