Figure 2.

Structural features of A. cellulolyticus ScaA CBM3b. (a) Overall structure. Cartoon representation of the major secondary-structural elements (numbered according to sequence). The N- and C-termini are indicated. Calcium and nickel ions are shown as spheres (blue and orange, respectively). The solvent-accessible surface calculated using PyMOL is shown. (b) Space-filling representation of the proposed cellulose-binding region. Upper view; residues forming the cellulose-binding strip are coloured by element (carbon, yellow; oxygen, red; nitrogen, blue) and numbered. (c) Lateral view presenting the planar face that is free from topographic obstacles that could interfere in the formation of interactions with the glucose rings of the cellulose.