Extended Data Fig. 10: Supporting information for the CUL2^LRR1 structure and its interaction with the H. sapiens replisome.

a, Structural overlay of aligned model from replisomes bound to CUL2^LRR1 (blue) and in the absence of CUL2^LRR1 (red). b, Composite model and map representing the conformational variability of CUL2/RBX1. The model for the replisome, bound to LRR1 and ELOB-ELOC, is displayed using pipes and planks rendering and coloured according to subunit. Three representative 3D classes are displayed encompassing density for CUL2:RBX1 obtained through 3D classification without alignment. The distance between RBX1 and K29_MCM7 is indicated as a dotted orange line and distances denoted in the inset key. c, Overview of the interface between the LRR1 PH domain and the replisome. Subunits interacting with the LRR1 PH domain are displayed using transparent surface rendering. Boxed regions indicate key interaction interfaces expanded in panel d. d, Detailed structural views of the interface between the LRR1 PH domain and 1: TIMELESS, 2(A): MCM6 ZnF, 2(B): dsDNA and 3: MCM2 ZnF. e, Model for the LRR1 LRRs with numbering indicating the order of the leucine-rich repeats. f, Consensus motif for the LRR1 LRRs. The sequence of each repeat is indicated with the positions of the key L₀, L₃ and L₅ residues highlighted in red. Repeats 1 and 9 represent irregular LRRs. L is Leu/Val/Ile/Phe, N is Asn/Thr/Cys, x is any amino acidL is Leu/Val/Ile/Phe, N is Asn/Thr/Cys, x is any amino acid. g, LRR1 model docked into transparent cryo-EM density with the capping 2-stranded β-sheet highlighted in gold. h, Overview of the LRR1:ELOB:ELOC:CUL2:AND-1 interface. Models displayed docked into transparent cryo-EM density with MCM subunits visualised using surface rendering. i, Structure of the AND-1 HMG box (PDB:2D7L) docked into the AND-1-dependent cryo-EM density adjacent to ELOC and LRR1. Selected hydrophobic core residues displayed. j, Map of the replisome bound to CUL2^LRR1 in the absence of AND-1 coloured according to subunit. k, Cryo-EM density of the LRR1:ELOB:ELOC:CUL2 interface obtained through multi-body refinement from particles lacking AND-1. The density attributed to the AND-1 HMG box is dependent upon AND-1. l, Overview of the MCM:LRR1^LRR interface. MCM subunits displayed with additional transparent surface rendering and the order of the LRR1^LRRs numbered. Red-dashed boxes indicate key interaction sites, expanded in panel m. m, Detail of the MCM:LRR1^LRR interface involving contacts between the LRR1^LRRs and 1 - MCM3, 2 - MCM5 ZnF and 3 - the MCM7 N-terminus. n, Model highlighting local rearrangements of MCM3 upon binding CUL2^LRR1. Structures in the absence (top) and presence (bottom) of CUL2^LRR1, coloured according to inset key, highlight the rearrangement of MCM3_(1-9) and MCM3_(164-174). o, Comparison of the CUL2^LRR1-interacting regions of MCM from complexes assembled on a DNA substrate either lacking a 5′-flap (green) or containing a 15 nucleotide 5′-flap (gold, PDB: 7PFO²⁸). Complexes lacked CUL2^LRR1. The r.m.s.d. between the two structures for the region shown is 0.43 Å.