FIG. 4.

AFM images of fixed, hSWI/SNF (S/S)-remodeled arrays on spermidine-treated mica. (A) An array from the control reaction mixture lacking ATP (Fig. 3B, lane 5). (B) Arrays remodeled by hSWI/SNF and ATP for 90 min (Fig. 3B, lane 4). (C) Histogram of internucleosomal distances (peak to peak along the DNA contour) from two experiments. The data (23 arrays with ATP, 19 arrays without ATP) were grouped into three bins (≤14 nm, 14 to 60 nm, and >60 nm) and normalized to 100%. (D) An hSWI/SNF-bound array from the same control reaction mixture as in panel A. (E) An hSWI/SNF-bound remodeled array from the same reaction mixture as in panel B. The arrow shows potential DNA loops constrained by SWI/SNF. The height range in panels D and E is greater than in that in panels A and B to allow structural features of SWI/SNF to be evident.