Figure 4

Gg NEU3 structure prediction. Top (A) and lateral (B) view of the 3D model of Gg NEU3 predicted using SWISS-Model. The numbers (1-6) in (A) indicate the six blades of the β-propeller and the black arrow in (B) indicates the catalytic crevice. The 6 blades of the β-barrel are shown with the same color code used in Figure 2. The first six non-conserved repeat units of the loop have been removed in this representation. First (Thr-318) and last (Gly-495) amino acids of the deleted region are indicated in red. (C) Topology diagram representing the arrangement of the fifth blade of the β-propeller. The blue arrows indicate β-strand and conserved amino acid blocks surrounding the repeat region are indicated with white letters. The repeat region between the Thr-318 and Gly-495 residues is represented by a red dotted line, whereas the other loop regions of the blade are represented by black lines. The catalytic residue Arg-518 is indicated in green. (D) Ab initio structure prediction of the loop region of Gg NEU3 (from Thr-318 to Gly-495). The loop-supporting region described in results is colored in red. The arrows indicate putative β-sheet regions within the structure as predicted by PSIPRED. (E) Detail of the support region of the Gg NEU3 loop. The first 12 residues of the loop are represented in green and the last 44 in magenta. Amino acids involved in hydrogen bonds or hydrophobic interactions are represented with sticks and linked with black dotted lines.