Fig. 6.

CENP-A- and H3-containing nucleosomes are structurally distinct. a Crystal structure of nucleosomes containing canonical H3 (green) or CENP-A (orange) by in silico homology models are superimposed. Boxes highlight differences in their L1 loop structures (b) and in the organization of the N-terminal helix with regard to nucleosomal DNA (c). H2A, H2B, and H4 are in blue and DNA is in beige. b The L1 loop of CENP-A contains two additional amino acids and protrudes further from the nucleosome than that of canonical H3. c The N-terminal helix of CENP-A is shorter than the corresponding region in H3, and the DNA at this region (dashed line) may be more flexible in CENP-A nucleosomes