Fig. 7: The proposed “Dynamic-Anchor” model of sequence-adaptive DNA recognition.

Schematic model showing three phases of DNA binding. Phase I (IDR-guided promoter scanning): The highly flexible terminal regions of AflR-DBD engage in transient, non-specific interactions with DNA to facilitate rapid scanning of potential binding sites. Phase II (Zinc cluster motif anchoring): The structured zinc cluster motif recognizes and binds to specific CG half-sites within different promoters through precise major groove contacts, serving as a stable molecular anchor. Phase III (IDR-mediated binding optimization): The dynamic terminal regions mediate the protein undergo conformational changes to establish distributed, weak interactions across the DNA binding interface, optimizing the binding specificity and stability. Orange spheres represent the zinc cluster motif; gray, blue, and red lines indicate terminal IDRs; turquoise dots mark CG binding sites; and the gray double helix represents DNA.