Figure 1.

Kinetic studies of non‐enzymatic ligation reactions. a) Illustration of experimental design. The 5′‐fluorescently labelled primer contains either a ribonucleotide (C_OH) or a 3′‐amino‐2′,3′‐dideoxyribonucleotide (C${}_{\mathrm{NH}{}_2}$ ) at the 3′‐terminus. The template is complementary to the primer and has a 5′‐UCAG overhang. The ligator is 2‐MeImp‐CUGA. All experiments were carried out with 2 μm primer, 4 μm template, 200 mm HEPES, pH 8.0, and 100 mm MgCl₂ unless otherwise noted, and with the indicated concentration of the tetramer ligator. Excess template was used to ensure that all primer was template bound and to avoid non‐templated ligation reactions. b–e) Ligator‐concentration dependence of the ligation rate under different conditions: b) RNA primer; c) 3′‐amino primer; d) RNA primer with 100 mm HEI; e) 3′‐amino primer with 100 mm HEI. Black circles=100 mm MgCl₂. blue triangles=no MgCl₂. Data points are reported as the mean±s.d., n≥3.