CAL1 binds CENP-A–H4, but not H3–H4. SEC elution profiles (separated in two graphs for clarity) of equal concentration of: (A) refolded CAL11–160, CENP-A101–225, and H4; (B) refolded CAL11–160, H3, and H4. Colored lines show the content of the components being co-purified in each case. (C) SDS-PAGE analysis of fractions from the peaks (P) shown in A and B, color coded as therein. Lanes 1–3: P4 of H3 + H4 alone; lanes 4–7: P1 of CENP-A101–225 + H4 (free CENP-A/H4 tetramer, predicted size 52 kD); lane 8: P2 from CAL11–160 alone; lanes 9–14: P3 from CAL11–160 + CENP-A101–225 + H4 (complex predicted size 43 kD); lane 15: P4a (free H3/H4 tetramer, predicted size 52 kD) from CAL11–160 + H3 + H4; lanes 16–21: P2a (free CAL11–160).