FIG. 1.

(A) Modular architecture of the α-agarase AgaA_Aa. CBM6 and GH96 refer to carbohydrate-binding modules of family 6 and the glycoside hydrolase module of family 96, respectively. Gray boxes correspond to the TSP3 repeats. (B) Structure-based alignment of the TSP3 repeats of the human thrombospondin (PDB code 1UX6), of the α-agarase AgaA_Aa, and of the cellulase CelG from Pseudoalteromonas haloplanktis (trEMBL code O86099). (C) Structure-based alignment of the three CBM6s from the α-agarase AgaA_Aa and of the agar-specific CBM6s tethered to the β-agarases Aga16B_Sd (GenPept no., ABD80437) and Aga86E_Sd (GenPept no., ABD81915) from Saccharophagus degradans. These modules are compared to the secondary structures of the CBM6 appended to Aga16B_Sd (PDB code 2CDO). Alpha helices and beta strands are represented as helices and arrows, respectively, and beta turns are marked with TT. The black triangles mark the residues involved in the recognition of the nonreducing end of agarose chains. Figure 1B and C were prepared using ESPrit software (7) and use the same shading codes.