Figure 5

Model of the Ap-B structure, consensus motifs and Zn²⁺ close residues. (A) Domain structure of rat Ap-B according to [27]. The NH₂-terminal, catalytic and COOH-terminal domains are colored in green, red and purple, respectively. The Zn²⁺ ion is depicted as a sphere and colored in grey. (B) Representation of the domain structure of rat Ap-B supported by multiple sequence alignments and conserved amino acid residues using the same colors than above. (C) Representation of the Proline-rich loops (position 47–57 and 485–499; depicted as space fill) and of the putative RNP1 consensus motif (position 416–423; depicted as ball-and-stick) on the whole Ap-B structural model. (D) Magnification of the catalytic centre showing the high proximity between the Zn²⁺ ion (grey sphere) and, on one hand, the three Zn²⁺ ligands (His³²⁴, orange ; His³²⁹, green ; Glu³⁴⁸, blue) and, on the other hand, the catalytic residue Glu³²⁵ (yellow) and the putative proton donor in the catalytic reaction (Tyr⁴¹³, light green). The remaining part of the structure is depicted as transparent material. The figure was created using the molecular graphics software Visual Molecular Dynamics (VMD 1.8.2; [60].