PF3D7_1003500

PF3D7_1003500 (S20e) is established solely as a structural component of the small (40S) subunit of the Plasmodium falciparum 80S ribosome, resolved within high-resolution cryo-EM structures of the intact ribosome (PMID:24913268, PMID:26432834) and visualized in situ as part of natively translating ribosomes inside infected human erythrocytes (PMID:40825879). No enzymatic activity, specific binding partner, or functional role for S20e beyond its incorporation into the ribosome has been characterized in the available corpus; the studies that place S20e in the small subunit interrogate ribosome-level features—such as the emetine binding site at the small-subunit E-site that blocks mRNA/tRNA translocation (PMID:24913268) and drug-induced shifts in elongation-factor-bound states (PMID:40825879)—rather than S20e itself. Beyond its membership in the 40S subunit, S20e has not been individually functionally dissected in the available corpus.

1. 2014 Medium

   Establishing the molecular composition of the P. falciparum small ribosomal subunit required a high-resolution structure; resolving S20e as a subunit component defined it as part of the parasite translation machinery and situated it near the emetine/E-site translocation region.

   Evidence Cryo-EM structure of the P. falciparum 80S ribosome-emetine complex at 3.2 A

   PMID:24913268

   Open questions at the time

   • S20e is placed structurally but not functionally interrogated
   • No test of whether S20e itself contributes to emetine binding or translocation
   • No binding partners or activity assigned to S20e
2. 2015 Medium

   Confirming S20e as a bona fide component of the native ribosome (not a preparation artifact) required independent reconstructions from parasite-derived material, reinforcing its assignment to the small subunit.

   Evidence Five cryo-EM reconstructions of ribosomes purified from blood-stage schizonts with flexible-fitting atomic models

   PMID:26432834

   Open questions at the time

   • No functional role for S20e distinguished from bulk ribosome
   • No stage-specific or condition-specific role tested for S20e
   • Single lab
3. 2025 Medium

   Whether S20e is part of ribosomes actively translating in the cellular context was addressed by in situ imaging, confirming its presence in native translating ribosomes and linking the ribosome to drug-responsive translational states.

   Evidence In situ cryo-electron tomography of translating ribosomes inside P. falciparum-infected erythrocytes with a Plasmodium-specific translation inhibitor

   PMID:40825879

   Open questions at the time

   • Drug-induced changes are ribosome-level, not attributed to S20e specifically
   • No S20e-specific perturbation or knockdown
   • No interaction partners beyond the ribosome assigned to S20e

• Whether S20e has any function beyond serving as a structural subunit—any regulatory, extra-ribosomal, or drug-target role—remains unaddressed.
• No genetic perturbation of S20e reported
• No S20e-specific binding partners or post-translational modifications characterized
• No evidence of function outside the ribosome