Figure 3

Structural basis of ABA recognition by FePYR1. (A) 2Fo-Fc electron density map of ABA and its surrounding residues contoured at 1.0 σ. (B) The mono-methyl and the dimethyl groups of ABA are surrounded by stereo-selective residues of FePYR1. (C) Schematic presentation of the interactions between bound ABA and FePYR1 binding pocket residues within 4 Å. Charged interactions and hydrogen bonds are indicated by arrows, hydrophobic interactions indicated by solid lines. (D,E) Overlap of FePYR1 (green) with AtPYR1-HAB1 complex (gray). The differential gate and latch loop of FePYR1 (green) and AtPYR1 complex (gray) (PDB code: 3qn1) are indicated by arrows in (D). (E) Enlarged interface interacting with AtHAB1 indicated by dash line box in (D). (F,G) Mutations of the key residues in the binding pocket, gate and latch regions of FePYR1 compromise its interactions with AtHAB1 in the presence of ABA at concentrations of 100 μM (F), 10 μM and 2 μM ABA (G).