Structural basis for translation termination on the 70S ribosome
Abstract
At termination of protein synthesis, type I release factors promote hydrolysis of the peptidyl-transfer RNA linkage in response to recognition of a stop codon. Here we describe the crystal structure of the Thermus thermophilus 70S ribosome in complex with the release factor RF1, tRNA and a messenger RNA containing a UAA stop codon, at 3.2Å resolution. The stop codon is recognized in a pocket formed by conserved elements of RF1, including its PxT recognition motif, and 16S ribosomal RNA. The codon and the 30S subunit A site undergo an induced fit that results in stabilization of a conformation of RF1 that promotes its interaction with the peptidyl transferase centre. Unexpectedly, the main-chain amide group of Gln230 in the universally conserved GGQ motif of the factor is positioned to contribute directly to peptidyl-tRNA hydrolysis.
- Publication:
-
Nature
- Pub Date:
- August 2008
- DOI:
- 10.1038/nature07115
- Bibcode:
- 2008Natur.454..852L