AFM imaging of protein movements: histone H2A-H2B release during nucleosome remodeling.

Being able to follow assembly/disassembly reactions of biomolecular complexes directly at the single molecule level would be very useful. Here, we use an AFM technique that can simultaneously obtain topographic images and identify the locations of a specific type of protein within those images to monitor the histone H2A component of nucleosomes acted on by human Swi-Snf, an ATP-dependent nucleosome remodeling complex. Activation of remodeling results in significant H2A release from nucleosomes, based on recognition imaging and nucleosome height changes, and changes in the recognition patterns of H2A associated directly with hSwi-Snf complexes.