FIGURE 10.

Kinetic study of the MSL1L2 HHRz with a phosphorothioate 5′ to A9 (A9 PS). Rate curve of WT MSL1L2 (black) and MSL1L2 with a mixture of R_p and S_p phosphorothioate diastereomers 5′ to A9 in 500 μM Mg²⁺ (red) and 10 μM Cd²⁺ (blue). Studies were performed in 5 mM HEPES (pH 7.0) and 100 mM Na⁺. Data are fit to a biphasic rate equation (Equation 2). In 500 μM Mg²⁺ a fast k_obs of 2.3 min⁻¹ and slow k_obs of 0.08 min⁻¹ are obtained for the WT MSL1L2 and a fast k_obs of 3.2 min⁻¹ and slow k_obs of 0.15 min⁻¹ are obtained for the A9 PS. In 10 μM Cd²⁺ a fast k_obs of 2.2 min⁻¹ and slow k_obs of 0.06 min⁻¹ are obtained.