Figure 5. Binding of MPA to the enzyme-GMP complex inhibits the interaction with RNA.

(A) The enzyme-GMP complex was incubated with a radiolabeled RNA substrate (3 µM) of 81 nucleotides in the presence of increasing concentrations of MPA. UV-cross-linking assays were performed to monitor the binding of radiolabelled RNA to the enzyme-GMP complex and visualized by SDS-PAGE analysis and autoradiography. (B) The reaction products were quantified by phosphorimaging.