Small ribosomal subunit (SSU) (SSU)

The small ribosomal subunit (SSU) of Leishmania is a fundamental component of the parasite's protein synthesis apparatus, playing a central role in the decoding of messenger RNA (mRNA). While Leishmania is a eukaryotic organism possessing an 80S ribosome, its small subunit (conventionally the 40S subunit) features a decoding site that is structurally prokaryotic-like, making it a selective target for certain aminoglycoside antibiotics. Drugs such as paromomycin (aminosidine) exert their antileishmanial effects by binding to the A-site of the 18S ribosomal RNA within this subunit. This interaction disrupts the fidelity of translation, leading to mRNA misreading and the inhibition of ribosomal translocation, which ultimately results in the production of aberrant proteins and parasite cell death. This target is clinically validated, with paromomycin being a primary treatment for visceral leishmaniasis, although therapeutic use is limited by risks of ototoxicity and nephrotoxicity due to potential interactions with host mitochondrial ribosomes. The emergence of drug-resistant strains also poses a significant challenge to the long-term efficacy of targeting this subunit.

Other names

40S ribosomal subunit18S ribosomal RNALeishmania ribosome30S-like ribosomal subunit30S ribosomal subunit – Leishmania/prokaryotic-like

Inhibition of protein synthesis by binding to the decoding site (A-site) of the small ribosomal subunit, leading to mRNA misreading and inhibition of translocation.