Fig. 2
From: Structural and biochemical insights into small RNA 3′ end trimming by Arabidopsis SDN1
The SDN1 catalytic pocket and mechanisms of its RNA recognition. a–c Interactions between the SDN1 catalytic pocket and the four nucleotides from the 3′ end of the RNA. Hydrogen bonds are colored in red. d Active center of SDN1. Two magnesium ions are shown with the simulated annealing Fo-Fc omit map (contoured at 5.0 σ level), and there is no electron density for MgA due to low occupancy. e Schematic drawing of the interactions between the SDN1 catalytic pocket and the RNA substrate. f In vitro enzymatic activity assays with wild-type SDN1, SDN1 ΔC, and various SDN1 mutants. Wild-type SDN1 can degrade the free miRNA into products of a very small size. SDN1 ΔC and the mutants are defective in enzymatic activity
