Figure 2
Three-dimensional structure and ligand binding of the T. pinophilus GH62 arabinofuranosidase in complex with the inhibitor AraDNJ. (a) Three-dimensional structure colour-ramped from the N-terminus (blue) to the C-terminus (red). Metal ions are shown as shaded spheres and AraDNJ as a CPK model. (b) The chemical structure of AraDNJ. (c) ITC data for AraDNJ binding (Kd of 24 ± 0.4 µM). (d) Observed electron density for AraDNJ bound to GH62, 2Fo − Fc (maximum-likelihood/σA-weighted) at 1.25 Å contoured at 1σ. The catalytic acid Glu212 and base Asp52 are shown, along with a water molecule poised for nucleophilic attack. (e) Partial overlay of the T. pinophilus GH62 arabinofuranosidase (brown with AraDNJ in green) with the S. coelicolor GH62 arabinofuranosidase (PDB entry 3wn2; pale blue with xylopentaose in green), highlighting the highly conserved binding centre and the recognition apparatus for the arabinoxylan chain. Structural figures were drawn with CCP4mg (McNicholas et al., 2011). |