Figure 6

Modeling of the CBM1s from the CBEL protein. A) Multiple sequence alignment of CBEL_CBM1-1, CBEL_CBM1-2 with the CBM1 of cellobiohydrolase I from Trichoderma reesei (TrCBM1, Uniprot/KB accession number: P62694). Amino residues putatively important for binding to crystalline cellulose are in bold and underlined. B) Comparison of the lateral faces of the ribbon diagrams of TrCBM1 (left) and CBEL_CBM1-1 (right). The strands of the β-sheet are numbered β1, β2 and β3 from the N- to the C-terminus. The aromatic residues involved in the binding to cellulose are displayed in grey ball-and-sticks. The Asn (replaced by Ser in CBEL_CBM1-2) and Trp residues susceptible to interact with cellulose are similarly displayed in grey ball-and-sticks. The four Cys residues linked to disulphide bonds (dashed lines) are displayed in black ball-and-sticks and numbered. C). Precise view of the binding model of CBM1s from TrCBM1 and CBEL. Only the aromatic residues (Phe and Tyr) stacking on the pyranose ring of the glucose units and close hydrophilic residues (Gln, Asn and Ser) susceptible to create hydrogen bonds with the hydroxyls of the glucose units, are displayed in black ball-and-sticks. Only six β1,4-linked glucose units are drawn in grey ball-and-sticks. Cartoons are drawn with Molscript[67], and rendered with Raster3D[68]