title: The beta subunit of Aquifex aeolicus leucyl-tRNA synthetase is responsible for cognate tRNA recognition.
abstract: The active form of the leucyl-tRNA synthetase from an extreme thermophile Aquifex aeolicus has a heterodimeric (alpha/beta type) quaternary structure that is unique among class I aminoacyl-tRNA synthetases. In an attempt to clarify the individual roles of each subunit in the function of leucyl-tRNA synthetase, several elementary activities were separately measured using each of the subunits alone or the reconstructed alpha/beta complex. It was found that the beta subunit alone is capable of recognizing its cognate tRNA, while the leucyl-adenylate formation and the overall leucyl-tRNA formation are detected only when both of the subunit proteins coexisted.
mesh_terms: D001419:Bacteria / Q000201:enzymology* / Q000235:genetics; D001665:Binding Sites; D019281:Dimerization; D005798:Genes, Bacterial; D006358:Hot Temperature; D007935:Leucine-tRNA Ligase / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D021122:Protein Subunits; D012329:RNA, Bacterial / Q000378:metabolism; D012343:RNA, Transfer / Q000737:chemistry / Q000378:metabolism*
chemical_list: D021122:Protein Subunits; D012329:RNA, Bacterial; D012343:RNA, Transfer; D007935:Leucine-tRNA Ligase