Supplementary Figure 2: Selective details of intermolecular contacts of our crystal structures and biochemical characterizations of different MCM2 HBD–H3–H4 –ASF1 complexes.

(a–c) Each panel highlighting the key interactions in the S1 (panel a), S2 (panel b) and S3 (panel c) regions of MCM2 HBD in the MCM2 HBD–H3–H4 tetramer complex. (d) GST-pulldown of ASF1 WT and V94R mutant with recombinant H3–H4 tetramers and prepurified MCM2 HBD–H3–H4 tetramer complex. (e) The prepurified MCM2 HBD(43–160)–H3–H4 tetramer (P1), ASF1b(1–158) (P3) and MCM2 HBD(43–163)–H3(EE) –H4 dimer (a constitutive H3–H4 dimer with dual mutation L126E I130E on H3) (P4) were analyzed by gel filtration and served as controls; the prepurified MCM2 HBD(43–160)–H3–H4 tetramer (20 nmole) was incubated with ASF1b(1–158) (12 nmole) and the reaction mixture was analyzed. Two peaks P1’ (not reacted complex) and P2 (reaction product) were expected and observed. (f) The peak fractions from panel e were analyzed on SDS-PAGE. (g) The MCM2 HBD(61–130)-linker-ASF1b(1–158)–H3.3(Δ56) –H4 dimer (complex 3) and MCM2 HBD(43-160)–H3.2(Δ55) –H4 dimer–ASF1a(1–172) (complex 4) were analyzed as in panel b of Supplementary Fig. 1. (h) SDS-PAGE analysis of the peak fractions from panel g. (i–k) Each panel highlighting the key interactions in the S1 (panel i), S2 (panel j) and S3 (panel k) regions of MCM2 HBD in the MCM2 HBD–H3–H4 dimer–ASF1 complex. For clarity, the ASF1 segment was omitted in panel k.