Structure of d-Aminopeptidase DAP

Surface representation of the substrate binding site of DAP. The substrate binding site of DD-peptidase (PDB ID 1IKG) complexed with REX (ball and stick representation) is also superposed to that of DAP. 

Overall structure of DaaA com-plexed with D-Phe (ball and stick representation). SerGO is represented as ball and stick, and El 14 and Q310 are represented as cylinders. Salt bridge and hydrogen bond are represented as broken lines. Q- and L3-loops and residues 278-290 are represented as black. 

A previous study reported that DaaA lacked aminopeptidase and carboxypepti-dase activities [5]. The absence of these activities may be attributed to the steric hindrance of the substrate-binding pocket by residues 278-290 and the Q-loop. 

---