Fig. 3

Cartoon representation of the crystal structures of enzymes. a Variant QW4. b Variant QW10. c WT CALB (PDB: 5a71²¹). a–c are colored according to the B-factor. d Superimposed overall structures of WT CALB (gray), QW4 (green) and QW10 (pink). e Zoom-in view of the loop 137–150 in WT CALB (gray), in QW4 (green) and in QW10 (pink). f Zoom-in view of helix 277–288 in WT CALB (gray), in QW4 (green) and in QW10 (pink). Hydrogen bonds formed between the α-6 helix, loop 137–150 and α-10 helix in g (WT-CALB), h (QW4) and i (QW10). H-bond formed between Tyr281 and Glu188 in QW4 mutant (h) was also noted