Recognition of tRNAGln by Helicobacter pylori GluRS2--a tRNAGln-specific glutamyl-tRNA synthetase.
Accurate aminoacylation of tRNAs by the aminoacyl-tRNA synthetases (aaRSs) plays a critical role in protein translation. However, some of the aaRSs are missing in many microorganisms. Helicobacter pylori does not have a glutaminyl-tRNA synthetase (GlnRS) but has two divergent glutamyl-tRNA synthetases: GluRS1 and GluRS2. Like a canonical GluRS, GluRS1 aminoacylates tRNA(Glu1) and tRNA(Glu2). In contrast, GluRS2 only misacylates tRNA(Gln) to form Glu-tRNA(Gln). It is not clear how GluRS2 achieves specific recognition of tRNA(Gln) while rejecting the two H. pylori tRNA(Glu) isoacceptors. Here, we show that GluRS2 recognizes major identity elements clustered in the tRNA(Gln) acceptor stem. Mutations in the tRNA anticodon or at the discriminator base had little to no impact on enzyme specificity and activity.
Chang
Keng-Ming
KM
Department of Chemistry, Wayne State University, Detroit, MI 48202, USA.
Hendrickson
Tamara L
TL
D000926:Anticodon; D005975:Glutamate-tRNA Ligase / Q000378:metabolism*; D016480:Helicobacter pylori / Q000201:enzymology*; D016296:Mutagenesis; D012351:RNA, Transfer, Gln / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity
D000926:Anticodon; D012351:RNA, Transfer, Gln; D005975:Glutamate-tRNA Ligase