Bacterial 23S ribosomal RNA helix 69 (H69)

Bacterial 23S ribosomal RNA helix 69 (H69) is a highly conserved 19-nucleotide hairpin loop located within Domain IV of the 23S rRNA of the 50S ribosomal subunit. It plays a pivotal role in protein synthesis by forming the inter-subunit bridge B2a, which connects the 50S subunit to the 30S subunit via interactions with helix 44 of the 16S rRNA (Yusupov et al., 2001, Science). This bridge is essential for maintaining the structural integrity of the ribosome and facilitating the movement of tRNAs during translocation (Ali et al., 2006, Molecular Cell). H69 is also involved in the ribosome recycling process, where it interacts with ribosome recycling factor (RRF) to promote subunit dissociation (Hirokawa et al., 2002, Molecular Cell). Because of its central role in translation, H69 is a critical target for several classes of antibiotics, including aminoglycosides and tuberactinomycins, which bind to this region to disrupt translocation and subunit recycling (Wang et al., 2012, Nucleic Acids Research). Targeting H69 is a proven strategy for treating various bacterial infections, although challenges such as drug-induced toxicity and the emergence of resistant strains through rRNA modification remain significant (Holm et al., 2016, Scientific Reports).

Other names

Helix 69H6923S rRNA H69Bridge B2a componentDomain IV helix 69

Binding to H69 stabilizes the inter-subunit bridge B2a, which inhibits the translocation of tRNAs and the dissociation of the ribosomal subunits during the recycling phase, thereby halting protein synthesis (Wang et al., 2012, Nucleic Acids Research; Hirokawa et al., 2002, Molecular Cell).