a) Human telomeric sequences wtTel26, wtTel24, and wtTel23, and their folding topologies. b,c) 1H NMR titration of EPI in K+ with wtTel24, (b) and wtTel23, (c), with the signature T-imino peak of the EPI-hybrid-2 complex marked by asterisk. d) CD titration spectra of EPI with wtTel26 in Na+ solution. e) Taq DNA polymerase stop assay using a DNA template containing a wt human telomeric sequence (bottom) showing EPI can induce telomeric G4 formation. Left 4 lanes are sequencing reactions.