Crystal structure of unlinked NS2B-NS3 protease from Zika virus

A closed conformation for Zika virus enzyme The recent Zika virus epidemic highlights the need for antiviral drugs. One important drug target is the virus's NS2B-NS3 protease, an enzyme that is critical for viral replication. Zhang et al. report high-resolution crystal structures of the protease as a free enzyme and with a peptide bound to the active site in the reverse position. The structures reveal that, unlike in other flaviviruses, the protease adopts a closed conformation, in which NS2B engages NS3 to form the empty substrate-binding site. Moreover, substrate binding did not substantially alter the conformation of the enzyme. Science , this issue p. 1597