Molecular determinants of complex formation between DNA and the AT-rich interaction domain of BAF250a.

AT-rich interaction domain (ARID)-containing BAF250a protein is a central DNA-binding subunit of the SWI/SNF chromatin-remodeling complex. ARIDs are found in several eukaryotic proteins that play roles in different aspects of cellular physiology. However, despite their biological importance, ARIDs remain relatively uncharacterized for their dynamics and DNA binding. Here, we have probed the structure and DNA-binding properties of BAF250a ARID. We show that the core BAF250a ARID interacts with DNA sequences with low micromolar affinities. NMR chemical shift perturbation (CSP) results reveal a number of conserved residues in ARID that are involved in DNA binding. An NMR CSP-based docking model of ARID-DNA complexes reveals that BAF250a ARID possesses necessary determinants of specific DNA binding.