FIGURE 5.

Selective degradation of 8-oxoGTP by MutT in the presence of a large amount of ATP, GTP, CTP, and UTP. The reaction mixture (25 μl) contained 1 μm 8-oxo-[¹⁴C]GTP, 0.9 mm GTP, 3 mm ATP, 0.52 mm CTP, 0.89 mm UTP, 1 ng of MutT, 20 mm Tris-HCl (pH 8), 8 mm MgCl₂, 40 mm NaCl, 5 mm DTT, 80 μg/ml BSA, and 2% (v/v) glycerol. The reaction was performed at 30 °C and terminated at 0 or 30 min by adding SDS (final concentration, 0.1%). The samples were resolved by HPLC with a Mono Q column. Nucleotides were separated with a linear gradient (5–100%) of 1 m triethylammonium hydrogen carbonate (pH 7.0) at a flow rate of 1 ml/min using HPLC.