Structure of an Escherichia coli Hfq:RNA complex at 0.97 Å resolution

In bacteria, small RNAs (sRNAs) silence or activate target genes through base pairing with the mRNA, thereby modulating its translation. A central player in this process is the RNA chaperone Hfq, which facilitates the annealing of sRNAs with their target mRNAs. Hfq has two RNA-binding surfaces that recognize A-rich and U-rich sequences, and is believed to bind an sRNA–mRNA pair simultaneously. However, how Hfq promotes annealing remains unclear. Here, the crystal structure of Escherichia coli Hfq is presented in complex with U₆-RNA bound to its proximal binding site at 0.97 Å resolution, revealing the Hfq–RNA interaction in exceptional detail.