Bacterial ribosome inter-subunit bridge B5 (Bridge B5)

The bacterial ribosome inter-subunit bridge B5 is a vital structural junction that maintains the association between the 30S (small) and 50S (large) ribosomal subunits, forming the functional 70S ribosome (Yusupov et al., 2001; PubMed: 11337585). This bridge is primarily composed of the ribosomal protein uL15 (formerly L15) and specific helices of the 23S ribosomal RNA (rRNA) from the 50S subunit, which interact with the 16S rRNA of the 30S subunit (Dunkle et al., 2011; PubMed: 21566187). It plays a crucial role in the structural dynamics of the ribosome, particularly during the translocation phase of translation where the subunits must undergo precise relative movements (Arenz et al., 2016; PubMed: 27161493). Because of its essentiality in bacterial protein synthesis, the B5 bridge is a target for specialized classes of antibiotics such as orthosomycins, including evernimicin and avilamycin (Belova et al., 2001; PubMed: 11158011). These drugs bind to the 50S subunit in close proximity to the B5 bridge, effectively blocking the assembly of the 70S initiation complex or hindering the recruitment of translation factors. Targeting this bridge offers a mechanism to combat multi-drug resistant bacterial infections, although the structural similarity between bacterial and human mitochondrial ribosomes necessitates careful evaluation of potential off-target toxicity (Wilson, 2014; PubMed: 24814403).

Other names

Inter-subunit bridge B5B5 bridgeuL15-23S-16S rRNA interfaceRibosomal bridge 5

Inhibition of 70S ribosome assembly and interference with translation factor binding by stabilizing or disrupting inter-subunit interactions.