Fig. 4

Modeling of the interface loops. a Extraction of parts of the sequence alignment of all modeled phosphorylases CdpA, CdpB, CdpC, and CbpA from R. cellulolyticum and C. thermocellum cellodextrin phosphorylase (5NZ8) as can be found in Additional file 2, showing the locations of the three loop regions L1, L2, and L3 which are forming the substrate-binding region beyond the cellobiose at the non-reducing end. Secondary structure from 5NZ8 (lower line) and the CdpA model (upper line) are also indicated, as well as locations of side chains Asp297 (magenta), Tyr300 (blue), and Tyr 804 (green) of 5NZ8 represented in triangles with their equivalent positions in the models as observed in the structural overlay represented in circles. b Zoom into the substrate-binding region of the Cα cartoon presentation of the modeled dimeric structures CdpA, CdpB, and CdpC in blue, cyan, and magenta, showing loop regions L1 in red, salmon, and light pink, L2 in green, blue–green, and olive, and L3 in yellow, light orange, and orange, respectively. The substrate in yellow is an overlay from 5NZ8