Figure 5. Exclusive CENP‐A nucleosome interaction around the RG loop with CENP‐C and CENP‐N.

1. Structural comparison of the CA‐CC^CT with CENPN‐NT (left) and CA‐CC^pep with CENPN‐NT (right). The cryo‐EM density maps of the CENPC‐CT fragment, CM peptide, and CENPN‐NT are indicated as a surface representation. The cryo‐EM density maps indicate that the structure of the CENP‐A nucleosomes bound with two CENPC‐CT fragments symmetrically (CA‐CC^CT complex) comprised approximately 94% of total analyzed particles. The RG loop^CENP‐A is occupied by CENPC‐CT in the CA‐CC^CT complex and thereby the CENPN‐NT could not access the same side of the nucleosome. The minor fraction (approximately 6% of total analyzed particles) comprised asymmetric CA‐CC^CT‐CN^NT complexes. In the structures of the CA‐CC^pep‐CN^NT (right), CM peptide and CENPN‐NT simultaneously bind to the CENP‐A nucleosome.
2. Side views of the CA‐CC^pep‐CN^NT and CA‐CC^CT complexes. The RG loop^CENP‐A binding site in each complex is indicated by a dotted circle.
3. The left panel contains the structure of the RG loop^CENP‐A binding site in the CA‐CC^pep‐CN^NT complex. R81^CENP‐A of the RG loop is recognized by CENPN‐NT. The right panel displays a superposition of the structure of CENPC‐CT in the CA‐CC^CT complex on the CA‐CC^pep‐CN^NT complex shown in the left panel. The model of CM peptide in the CA‐CC^pep‐CN^NT complex has been removed for clarity. The CENPC motif region in CENPC‐CT is shown in pink. Structural collision between the CM downstream region of CENPC‐CT and CENPN‐NT is shown at RG loop^CENP‐A in the CENP‐A nucleosome.