In vitro characterization of 6S RNA release-defective mutants uncovers features of pRNA-dependent release from RNA polymerase in E. coli

R9-33 mutant 6S RNA fails to release from Eσ⁷⁰. Binding and release capabilities were tested for different constructs and compared to the T1 RNA. Body-labeled RNA (left lane, both panels) was incubated with Eσ⁷⁰ (second lane of each panel), and rapid release was induced by the addition of MgCl₂ and NTPs. Time points were taken at 5, 60, and 90 min. The mobility difference between mutant RNA and the RNA:pRNA complex is indicated with black arrows.