FIGURE 4.

Effect of histone acetylation by Piccolo NuA4 on the structure of nucleosomes. Dye-labeled nucleosomes were incubated without (empty bar with thicker boarder) or with (light striped bar) Piccolo NuA4 for 30 min at 25 °C. A, FRET efficiency histograms of 601A nucleosomes upon incubation with or without Piccolo NuA4 in the presence of acetyl-CoA. B, FRET efficiency of 601A nucleosomes was decreased from 0.69 to 0.65 upon incubation, whereas there was no change in FRET before and after the incubation with the Piccolo NuA4 complex in the absence of acetyl-CoA. C, 601B nucleosomes displayed increased FRET efficiency from 0.55 to 0.58 upon incubation with Piccolo NuA4 in the presence of acetyl-CoA. D, only a minimal change in FRET was observed when nucleosomes were incubated with Piccolo NuA4 in the absence of acetyl-CoA. E, the same level of FRET change as in A was observed from 601A nucleosomes reconstituted with histones preacetylated with Piccolo NuA4 (i.e. no complex bound to the nucleosomes).