Figure 4.

Insertion of flexible polypeptide linkers does not compromise nucleosome sliding. (A) Schematic depiction of the nucleosome sliding assay. 25-mer nucleosomal arrays containing exposed AvaI restriction sites in the linker DNA were used to follow nucleosome sliding. Accessibility to AvaI (arrows) changes upon remodelling. Nucleosomes (ovals) and AvaI sites (x) are indicated. (B) ISWI_Wt and the insertion mutants were incubated with nucleosomal arrays for 3, 13 and 48 min, whereas ISWI_ΔHSS was incubated for 6 h. Control reactions (−) were depleted of ATP with apyrase before addition of ISWI and incubated for 6 h (ISWI_ΔHSS) or 48 min (all other enzymes). ISWI_Wt, wild-type ISWI.