title: A naturally occurring nonapeptide functionally compensates for the CP1 domain of leucyl-tRNA synthetase to modulate aminoacylation activity.
abstract: aaRSs (aminoacyl-tRNA synthetases) establish the rules of the genetic code by catalysing the formation of aminoacyl-tRNA. The quality control for aminoacylation is achieved by editing activity, which is usually carried out by a discrete editing domain. For LeuRS (leucyl-tRNA synthetase), the CP1 (connective peptide 1) domain is the editing domain responsible for hydrolysing mischarged tRNA. The CP1 domain is universally present in LeuRSs, except MmLeuRS (Mycoplasma mobile LeuRS). The substitute of CP1 in MmLeuRS is a nonapeptide (MmLinker). In the present study, we show that the MmLinker, which is critical for the aminoacylation activity of MmLeuRS, could confer remarkable tRNA-charging activity on the inactive CP1-deleted LeuRS from Escherichia coli (EcLeuRS) and Aquifex aeolicus (AaLeuRS). Furthermore, CP1 from EcLeuRS could functionally compensate for the MmLinker and endow MmLeuRS with post-transfer editing capability. These investigations provide a mechanistic framework for the modular construction of aaRSs and their co-ordination to achieve catalytic efficiency and fidelity. These results also show that the pre-transfer editing function of LeuRS originates from its conserved synthetic domain and shed light on future study of the mechanism.
authors.affiliation: State Key Laboratory of Molecular Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Tan
authors.forename: Wei
authors.initials: W
authors.lastname: Yan
authors.forename: Ru-Juan
authors.initials: RJ
authors.lastname: Liu
authors.forename: Meng
authors.initials: M
authors.lastname: Wang
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.forename: Xiao-Long
authors.initials: XL
authors.lastname: Zhou
authors.forename: En-Duo
authors.initials: ED
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D049148:Aminoacylation; D055162:Biocatalysis; D007935:Leucine-tRNA Ligase / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009174:Mycoplasma / Q000201:enzymology*; D010455:Peptides / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D010455:Peptides; D007935:Leucine-tRNA Ligase