Structural changes in the anti-silencing function 1 (Asf1)-H3/H4G94Pcomplex. (A) Superposition of the Asf1-H3/H4 and Asf1-H3/H4G94P structures. Asf1-H3/H4 (PDB:2HUE)  (gray) is superimposed on the Asf1-H3/H4G94P structure, colored as in Figure 1, with residue 94 in red. The direction of the 3-Å shift in the position of the histones in the Asf1-H3/H4G94P structure is indicated by an arrow. (B) Structural alignment of the H4 C terminal tail in the Asf1-H3/H4G94P (green) and Asf1-H3/H4 (gray) complexes. Nitrogen and oxygen atoms are colored blue and red, respectively.