A Legionella toxin exhibits tRNA mimicry and glycosyl transferase activity to target the translation machinery and trigger a ribotoxic stress response.

ABSTRACT: A widespread strategy employed by pathogens to establish infection is to inhibit host-cell protein synthesis. Legionella pneumophila, an intracellular bacterial pathogen and the causative organism of Legionnaires' disease, secretes a subset of protein effectors into host cells that inhibit translation elongation. Mechanistic insights into how the bacterium targets translation elongation remain poorly defined. We report here that the Legionella effector SidI functions in an unprecedented way as a transfer-RNA mimic that directly binds to and glycosylates the ribosome. The 3.1 Å cryo-electron microscopy structure of SidI reveals an N-terminal domain with an 'inverted L' shape and surface-charge distribution characteristic of tRNA mimicry, and a C-terminal domain that adopts a glycosyl transf

SUBMITTER: Subramanian A 

PROVIDER: S-EPMC11005034 | biostudies-literature | 2023 Nov

REPOSITORIES: biostudies-literature