FIGURE 2.

Gel mobility shift assay. (A) M1 RNA and C5 protein were allowed to form complexes under conditions similar to the ones used for Pb²⁺-induced cleavage but supplementing with 0.05% (w/v) Nonidet P40 and 5% (v/v) glycerol. Concentrations of C5 protein are given. M1 RNA was preincubated for 7 min at 37°C prior to mixing with freshly diluted C5 protein. The RNA–protein mixture was incubated for 10 more minutes before electrophoresis (see Materials and Methods). (B) RNase P holoenzyme activity test. Increasing concentrations of C5 protein were added at a constant concentration of M1 RNA (8 nM), with 300 nM of substrate (pATSerUG). Activity is expressed as the percentage of substrate cleaved/minute at steady state.