Fig. 4: Comparative analysis of the substrate binding profiles of PyAly, A1-II’, AlyV and AlyB revealed the relationship between the “-” section and product distribution.
a Structural comparison of the PyAlyH125A-M8 + M5 complex and the A1-II’-GGMG complex. The sugars bound in PyAly and A1-II’ are shown as sticks in yellow and gray, respectively. The substrate binding clefts of PL7 alginate lyases were divided into “+” sections and “-” sections using the cleavage site as the boundary. Similar substrate binding profiles at the “+” sections were observed. b Structural comparison of the PyAlyH125A-M8 + M5 and AlyVR91A-M8 complexes. The sugar bound in AlyV is shown in salmon. A clear angle was observed between the two sugar units at subsites -2, indicating different substrate binding profiles in the “-” sections. c Structural analysis of the AlyBH360A_Y466A-G9 complex. AlyB is shown in cartoon, and G9 is shown in green. The electron density map for G9 (contour level 1σ) is presented. The residues that formed hydrogen bonding interactions with subsites -3 to -1 are shown as sticks: the residues from CBM32 are in slate, and the residues from CD2AlyB are in gray. Hydrogen bonds are indicated with blue dashed lines.
