FIGURE 1.

Refolding of HCA with domain V rRNA and effect of 6AP. A, refolding of denatured HCA (final concentration of 300 nm) with various concentrations of domain V (Dom V) of 23S rRNA (E. coli; ●) and 25S rRNA (S. cerevisiae; ▴). The extent of refolding (30 min at room temperature) was estimated as the percentage of native HCA activity (stored undiluted in ice). The inset shows the effect of 6AP (300 μm) on HCA refolding without and with domain V rRNAs from E. coli and S. cerevisiae (S. cere). The results are the average of a minimum of three individual measurements, and error bars represent S.D. B, refolding of HCA (300 nm, 30 min at room temperature) in the presence of increasing concentrations of 6AP without (self-refolding; ■) or with (○) domain V of E. coli 23S rRNA (300–400 nm). The IC₅₀ (half-maximal inhibitory concentration) was determined from the x-intercept drawn at half-maximal refolding, taking the difference between the self-refolding and 23S rRNA domain V-assisted refolding as 100%. C, time course of HCA refolding without (self-refolding; ■) or with (○) domain V of 23S rRNA at different concentrations of 6AP (▴, ▿, and ☆). The curves were fitted with a single exponential equation using Origin 8.0, and the rates (mean of a minimum of three experiments) were estimated from the respective fits.