Figure 4.

Active site of EcAII in complex with l‐Asp. Structure No. 2 (complex between EcAII (wt) and l‐Asp at pH 5.6), was determined at 1.6 å and refined to R _work (R _free) = 0.130 (0.172). The stabilizing interaction (2.6 å) between Thr12 and the substrate is marked with thick dashed blue line. Also, well‐defined position of Tyr25 (in the closed state of N‐terminal hairpin) is shown. Two, invariant water molecules are labeled as w1 and w2