FIGURE 3.

Competition binding experiments to determine the Hfq surface that interacts with tRNAs. The complex between Hfq and ³²P-tRNA^Ala was preformed and then incubated with increasing amounts of A₁₈ or DsrA. DsrA and other ncRNAs have been previously shown to interact with the proximal face of the Hfq hexamer (Sledjeski et al. 2001; Mikulecky et al. 2004; T. Lee and A.L. Feig, unpubl.). Since only DsrA was able to compete with tRNA for binding to Hfq, this experiment establishes that tRNAs interact with some or all of the same binding surface as the ncRNAs.