Fig. 5: DNA binding is mediated by the β-cap of MEILB2–BRME1_MBD.

a Surface electrostatic potential of the MEILB2–BRME1_MBD modelled structure (red, electronegative; blue, electropositive). b SDS–PAGE of the supernatant (s) and pellet (p) following incubation of 30 μM MEILB2–BRME1_MBD wildtype (WT) and BRME1 R540E R549E mutation at 150 mM KCl in the presence or absence of 1 μM (per molecule) dsDNA (75 base pairs); representative of three independent experiments. c Pulldown using streptavidin magnetic beads of MEILB2–BRME1_MBD wildtype (WT) and BRME1 R540E R549E mutation in the presence or absence of a biotinylated dsDNA (75 base pairs) substrate; representative of three independent experiments. Electrophoretic mobility shift assays (EMSAs) analysing the ability of MEILB2–BRME1 (at molecular concentrations indicated) to interact with d dsDNA (300 base pairs) and e poly-dT ssDNA (75 bases), at concentrations of 50 μM per base/base pair. f Quantification of DNA binding by MEILB2–BRME1 through densitometry of EMSAs performed using 50 nM (per molecule) FAM-dsDNA (75 base pairs; blue) and 100 nM (per molecule) FAM-ssDNA (75 nucleotides; red). Plots, K_D and Hill coefficient (n) values were determined by fitting data to the Hill equation and are quoted within a 95% confidence interval; data are presented as mean values, with error bars indicating standard error, n  =  3 EMSAs. g The N-terminal β-cap of the MEILB2α–BRME1_MBD 2:2 core structure includes basic amino-acids MEILB2 K26 and BRME1 R540 and R549. EMSAs analysing the ability of MEILB2–BRME1_MBD (at molecular concentrations indicated) harbouring h MEILB2 K26E and i BRME1 R540E R549E mutations to interact with dsDNA (300 base pair) at concentrations of 50 μM per base pair. d, e, h, i Gel images are representative of at least three replicates performed using different protein samples. j Schematic of MEILB2–BRME1_MBD interacting via its β-cap with DNA. Source data are provided as a Source Data file.