Fig. 4.

Glycosylation of a 3′-OH acceptor using the 16MJ132 deoxyribozyme. Shown are the metal ion dependence using the 4-nitrophenyl α-D-Glc glycosyl donor 2b, as well as assay with the 4-nitrophenyl β-D-Glc glycosyl donor 1b. Incubation conditions: 70 mM HEPES, pH 7.5, 150 mM NaCl, combinations of 0.4 mM ZnCl₂, 20 mM MnCl₂, and 40 mM MgCl₂ as indicated, at 37 °C. The Zn²⁺ concentration was optimized; with 2b, similar k_obs and yield were observed with 0.2–0.5 mM Zn²⁺, whereas the yield was lower at or above 0.6 mM Zn²⁺ (data not shown). The metal ion combinations not shown, including Mn²⁺ or Mg²⁺ alone, had no activity.