Abstract
Impediments to DNA access due to assembly of the eukaryotic genome into chromatin are in part overcome by the activity of ATP-dependent chromatin-remodeling complexes. These complexes employ energy derived from ATP hydrolysis to destabilize histone-DNA interactions and alter nucleosome positions, thereby increasing the accessibility of DNA-binding factors to their targets. However, the mechanism by which theses complexes accomplish this task remains unresolved. We review aspects of nucleosome alteration by the SWI/SNF complex, the archetypal remodeling enzyme. We focus on experiments that provide insights into how SWI/SNF induces nucleosome movement along DNA. Numerous biochemical activities have been characterized for this complex, all likely providing clues as to the molecular mechanism of translocation.