Fig. 2.

Active site and internal cavity of ERAP1. (A) Bestatin binding to the active site of ERAP1. Bestatin is colored in orange and the surrounding electron density is an F_o-F_c map calculated in the absence of the molecule and drawn at 3.0σ. (B) Superposition of open (gray) and closed (colored) state of ERAP1. The movement of Tyr⁴³⁸ is highlighted and Phe⁴³³, which forms part of the S1 specificity pocket in the active protease is disordered in the open state. (C) Putative C-terminal substrate binding site within the internal cavity of ERAP1.