Insights into translocation mechanism and ribosome evolution from cryo-EM structures of translocation intermediates of Giardia intestinalis.

ABSTRACT: Giardia intestinalis is a protozoan parasite that causes diarrhea in humans. Using single-particle cryo-electron microscopy, we have determined high-resolution structures of six naturally populated translocation intermediates, from ribosomes isolated directly from actively growing Giardia cells. The highly compact and uniquely GC-rich Giardia ribosomes possess eukaryotic rRNAs and ribosomal proteins, but retain some bacterial features. The translocation intermediates, with naturally bound tRNAs and eukaryotic elongation factor 2 (eEF2), display characteristic ribosomal intersubunit rotation and small subunit's head swiveling-universal for translocation. In addition, we observe the eukaryote-specific 'subunit rolling' dynamics, albeit with limited features. Finally, the eEF2·GDP state featu

SUBMITTER: Majumdar S 

PROVIDER: S-EPMC10123126 | biostudies-literature | 2023 Apr

REPOSITORIES: biostudies-literature