Extended Data Figure 7: The C-terminal region of Acf1 is not required for specific binding to the H4 tail or for linker-length sensing by the ACF complex.
From: Histone H4 tail mediates allosteric regulation of nucleosome remodelling by linker DNA
a, Domain maps of WT and ΔC-term Acf1 (residues 1423–1556 deleted). b, Fluorescence anisotropy of TMR-labelled WT or 2RA H4-tail peptide in the presence of varying amounts of WT Acf1. In the 2RA H4-tail peptide, two charged arginines in the basic patch of the H4-tail peptide corresponding to the 2RA mutation in AutoN were replaced with alanines. Kd for the 2RA H4-tail peptide (41 ± 29 nM) is substantially higher than that of the WT H4-tail peptide (3 ± 9 nM). Data are presented as mean ± s.e.m. (error bars, 95% confidence intervals, n = 3 three independent titration experiments). When excess unlabelled H4-tail peptide was added to compete the TMR-labelled peptide off Acf1, the fluorescence anisotropy was reduced to the background level observed in the absence of Acf1. c, Fluorescence anisotropy of TMR-labelled H4-tail peptide in the presence of varying amounts of WT or ΔC-term Acf1. The measured Kd for ΔC-term Acf1 is 2 ± 7 nM, which is similar to that for WT Acf1 (3 ± 9 nM). Data are presented as mean ± s.e.m. (error bars, 95% confidence intervals, n = 3 independent titration experiments). d, Ensemble remodelling time courses of [WT H4, 78 bp], [WT H4, 40 bp] and [H4Δ1–19, 78 bp] nucleosomes by 40 nM WT (black/grey lines) and ΔC-term ACF (purple/light purple symbols) at 5 µM ATP.
