DNA‐Induced Entropic Gain Triggers an Allosteric Switch for Biomolecular Condensation of Heat Shock Transcription Factor 1

ABSTRACT The molecular logic of how site‐specific DNA recognition by a transcription factor (TF) is transduced into macroscopic protein condensation remains a fundamental puzzle in chemical biology. Here, we unveil that the structured DNA‐binding domain (DBD) of a TF acts as an entropic switch to regulate the release of the intrinsically disordered region (IDR). Using high‐resolution solution NMR spectroscopy, we demonstrate that DNA binding significantly shifts the conformational equilibrium of the DBD toward a highly dynamic state. This conformational shift allosterically triggers the release of the IDR, thereby promoting macroscopic biomolecular condensation via multivalent interactions between the IDR and other molecules. Our findings define a mechanism of entropy‐driven allostery, providing a structural and thermodynamic basis for how DNA‐encoded information is transduced into macroscopic phase behavior.