Structural basis for the FOXM1 DNA binding domain to specific dsDNA substrate

• High-resolution crystal structure of FOXM1-DBD bound to dsDNA reveals a canonical winged-helix fold with α3 inserted into the major groove. • Asn283, Arg286, and His287 form an essential triad for sequence-specific DNA recognition via hydrogen bonds and hydrophobic interactions. • Structure-guided mutagenesis and biophysical assays (ITC, EMSA) confirm the functional importance of these residues and reveal position-dependent tolerance to base substitutions in the FKH motif. • FOXM1 overexpression promotes cell proliferation and upregulates target gene transcription in a DBD-dependent manner, linking structural recognition to oncogenic function.