Enthalpic factors override the polyelectrolyte effect in the binding of EGR1 transcription factor to DNA

摘要: Protein-DNA interactions are highly dependent upon salt such that the binding affinity precipitously decreases with increasing concentration in a phenomenon termed polyelectrolyte effect. In this study, we provide evidence of EGR1 transcription factor to DNA displays virtually zero dependence on ionic strength under physiological concentrations and feat is accomplished via favorable enthalpic contributions. Importantly, unearth molecular origin enthalpy attribute it ability H382 residue stabilize EGR1-DNA interaction both intermolecular hydrogen bonding van der Waals contacts against backdrop salt. Consistent notion, substitution other amino acids faithfully restores salt-dependent canonical fashion. Remarkably, conserved across members EGR family, implying changes bulk unlikely play significant role modulating protein-DNA central family factors. Taken together, our study reports first example eukaryotic capable overriding polyelectrolye