Key result
KREPA2 strongly stimulates TbREL1 catalytic activity, with the interaction mediated by the final 59 C-terminal residues of TbREL1 and specific N-terminal residues like F206.
Identified critical regions and amino acids in TbREL1 that mediate interaction with KREPA2, essential for RNA editing in Trypanosoma brucei.
Suggests novel targets for trypanosome RNA editing inhibition; leaves open validation in disease models before therapeutic pursuit.
The Trypanosoma brucei parasite causes the vector-borne disease African sleeping sickness. Mitochondrial mRNAs of T. brucei undergo posttranscriptional RNA editing to make mature, functional mRNAs. The final step of this process is catalyzed by the essential ligase, T. brucei RNA Editing Ligase 1 (TbREL1) and the closely related T. brucei RNA Editing Ligase 2 (TbREL2). While other ligases such as T7 DNA ligase have both a catalytic and an oligonucleotide/oligosaccharide-binding (OB)-fold domain, T. brucei RNA editing ligases contain only the catalytic domain. The OB-fold domain, which is required for interaction with the substrate RNA, is provided in trans by KREPA2 (for TbREL1) and KREPA1 (for TbREL2). KREPA2 enhancement of TbREL1 ligase activity is presumed to occur via an OB-fold-mediated increase in substrate specificity and catalysis. We characterized the interaction between TbREL1 and KREPA2 in vitro using full-length, truncated, and point-mutated ligases. As previously shown, our data indicate strong, specific stimulation of TbREL1 catalytic activity by KREPA2. We narrowed the region of contact to the final 59 C-terminal residues of TbREL1. Specifically, the TbREL1 C-terminal KWKE (441-444) sequence appear to coordinate the KREPA2-mediated enhancement of TbREL1 activities. N-terminal residues F206, T264 and Y275 are crucial for the overall activity of TbREL1, particularly for F206, a mutation of this residue also disrupts KREPA2 interaction. Thus, we have identified the critical TbREL1 regions and amino acids that mediate the KREPA2 interaction.
No takes yet. Share an insight, caveat, or question.
Mehta et al. (2015) studied Trypanosoma brucei infection. TbREL1 mutations vs. Wild-type TbREL1 was evaluated on TbREL1 adenylylation and ligation activity. KREPA2 strongly stimulates TbREL1 catalytic activity, with the interaction mediated by the final 59 C-terminal residues of TbREL1 and specific N-terminal residues like F206.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: