Influence of the DNA substrate primer terminal sugar manifested
in ionic current traces for captured Φ29 DNAP complexes. (a)
DNA sequence of the hairpin primer–template substrates used
in the study. Each substrate features a 14-base pair duplex region
and a single-stranded template region of 35 nucleotides. The template
strands contain a reporter group of five consecutive abasic (1′,2′-H)
residues spanning positions +8 to +12 (indicated as red Xs in the
sequence). (b) Ionic current traces for individual binary complexes
formed between the D12A/D66A mutant of Φ29 DNAP with (i) DNA1-H_H,
which bears a 2′-H, 3′-H primer terminus, (ii) DNA1-OH_H,
which bears a 2′-OH, 3′-H primer terminus, (iii) DNA1-H_OH,
which bears a 2′-H, 3′-OH (natural deoxyribose) primer
terminus, or (iv) DNA1-OH_OH, which bears a 2′-OH, 3′-OH
(natural ribose) primer terminus. Complexes were captured at 180 mV.