Figure 7.

A proposed working model for the ternary BAM–LSF1–MDH complex in starch degradation. Left, LSF1 in complex with MDH functions as a scaffold anchored to the starch granule. Right, BAM1 (or BAM3) alone possesses weak starch hydrolysis activity. Middle panel, BAM1 (or BAM3)–LSF1–MDH exhibits strikingly increased starch degradation activity, generating more maltose products. Specifically, the N-terminal PDZ-BMI domain of LSF1 interacts with MDH and recruits BAM, whereas the C-terminal DSP-CBM segment of LSF1 binds to the polyglucan chain, anchors to the starch granule, and presents the polyglucan to the catalytic pocket of BAM, thus promoting starch degradation.