RNA size is a critical factor for U-containing substrate selectivity and permanent pseudouridylated product release during the RNA:Psi-synthase reaction catalyzed by box H/ACA sRNP enzyme at high temperature.
Fiche publication
Date publication
avril 2015
Auteurs
Membres identifiés du Cancéropôle Est :
Dr BRANLANT Christiane, Pr CHARPENTIER Bruno
Tous les auteurs :
Tillault AS, Fourmann JB, Loegler C, Blaud M, Branlant C, Charpentier B
Lien Pubmed
Résumé
The box H/ACA small ribonucleoprotein particles (H/ACA sRNPs) are RNP enzymes that isomerize uridines (U) into pseudouridines (Psi) in archaeal RNAs. The RNA component acts as a guide by forming base-pair interactions with the substrate RNA to specify the target nucleotide of the modification to the catalytic subunit Cbf5. Here, we have analyzed association of an H/ACA sRNP enzyme from the hyperthermophilic archaeon Pyrococcus abyssi with synthetic substrate RNAs of different length and with target nucleotide variants, and estimated their turnover at high temperature. In these conditions, we found that a short substrate, which length is restricted to the interaction with RNA guide sequence, has higher turnover rate. However, the longer substrate with additional 5' and 3' sequences non-complementary to the guide RNA is better discriminated by the U to Psi conversion allowing the RNP enzyme to distinguish the modified product from the substrate. In addition, we identified that the conserved residue Y179 in the catalytic center of Cbf5 is crucial for substrate selectivity.
Référence
Biochimie. 2015 Apr 17. pii: S0300-9084(15)00113-3