Fig. 3.

Increased flexibility at the αN helix of CENP-A in nucleosomal arrays. (A) Alignment of H3 and CENP-A sequences in the αN and adjacent loop region. Boxed region highlights the sequence of the representative peptides in B and C. (B) H/DX of a representative αN-H3 peptide from nucleosome arrays containing H3. Top panel shows normalized deuterium levels at each time point for arrays that are either “unfolded” (-Mg²⁺) or “folded” (+Mg²⁺) and bottom panels show raw peptide data where the dotted blue and pink lines are drawn as guides to visualize differences in H/DX and red arrows indicate peptide centroid values. (C) H/DX of a representative αN-CENP-A peptide from nucleosome arrays containing CENP-A. Top and bottom panels are displayed as in B. (D) Schematic representation of the locations where H3 αN helix contacts nucleosomal DNA. (E) MNase digestion of CENP-A or H3 containing nucleosome arrays.