Fig. 6

Model of B. coagulans NL01 AI trimer (a). The locations of the three substrate active sites (A,B,C) are close to the interface of two identical protein subunits. The model was constructed with the MODELLER module of Discovery Studio 4.0 package. Superimposition of the putative catalytic residues of BCAI (blue), L. fermentum CGMCC2921 AI (yellow, PDB ID: 4LQL) and E. coli AI (pink, PDB ID: 4F2D) (b). The complexes of BCAI active sites with L-arabinose (c) and D-galactose (d). The intermolecular H bonds are represented by green dotted lines. L-arabinose, D-galactose molecules and amino acid residues are displayed in stick form and colored according to elemental types