NMR structure of the A. aeolicus tmRNA pseudoknot PK1: new insights into the recoding event of the ribosomal trans-translation.
Résumé
The tmRNA pseudoknot PK1 is essential for bacterial trans-translation, a ribosomal rescue mechanism. We report the solution structure of PK1 from Aquifex aeolicus which, despite an unprecedented small number of nulcleotides and thus an unprecented compact size, displays a very high thermal stability. Several unusual structural features account for these properties and indicate that PK1 belongs to the class of ribosomal frameshift pseudoknots. This suggests a similarity between the mechanism of programmed ribosomal frameshifting and trans-translation.