title: Crucial role of the C-terminal domain of Mycobacterium tuberculosis leucyl-tRNA synthetase in aminoacylation and editing.
abstract: The C-terminal extension of prokaryotic leucyl-tRNA synthetase (LeuRS) has been shown to make contacts with the tertiary structure base pairs of tRNA(Leu) as well as its long variable arm. However, the precise role of the flexibly linked LeuRS C-terminal domain (CTD) in aminoacylation and editing processes has not been clarified. In this study, we carried out aspartic acid scanning within the CTD of Mycobacterium tuberculosis LeuRS (MtbLeuRS) and studied the effects on tRNA(Leu)-binding capacity and enzymatic activity. Several critical residues were identified to impact upon the interactions between LeuRS and tRNA(Leu) due to their contributions in the maintenance of structural stability or a neutral interaction interface between the CTD platform and tRNA(Leu) elbow region. Moreover, we propose Arg921 as a crucial recognition site for the tRNA(Leu) long variable arm in aminoacylation and tRNA-dependent pre-transfer editing. We also show here the CTD flexibility conferred by Val910 in regulation of LeuRS-tRNA(Leu) interaction. Taken together, our results suggest the structural importance of the CTD in modulating precise interactions between LeuRS and tRNA(Leu) during the quality control of leucyl-tRNA(Leu) synthesis. This system for the investigation of the interactions between MtbLeuRS and tRNA(Leu) provides a platform for the development of novel antitubercular drugs.
authors.affiliation: State Key Laboratory of Molecular Biology, Center for RNA research, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, People's Republic of China.
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Hu
authors.forename: Qian
authors.initials: Q
authors.lastname: Huang
authors.forename: En-Duo
authors.initials: ED
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D007935:Leucine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009169:Mycobacterium tuberculosis / Q000201:enzymology*; D017434:Protein Structure, Tertiary; D017393:RNA Editing; D012356:RNA, Transfer, Leu / Q000378:metabolism; D046249:Transfer RNA Aminoacylation; D020798:Two-Hybrid System Techniques
chemical_list: D012356:RNA, Transfer, Leu; D007935:Leucine-tRNA Ligase