fig4

Figure 4. Comparison of amino acid residues at the catalytic site among Bifidobacterium GH39s. A: Comparison of amino acid residues at the catalytic sites, according to a previous report^[24]. Catalytic residues (red) and residues with variation (yellow) across GH39 sequences are presented. The phylogenetic tree depicted on the left was constructed via the neighbor-joining method based on aligned Bifidobacterium GH39 sequences. GH39 sequences were aligned using the Clustal W program via MEGA11 software; B: The predicted structures of AAfase (left) and GAfase (right) are depicted as a surface representation. AlphaFold2 (ColabFold) was used to obtain the structural model with default settings. Predicted catalytic residues are highlighted in red, and different amino acid residues (Tyr¹¹⁶ in AAfase and Asn¹¹⁹ in GAfase) are highlighted in yellow.