A bridge between the aminoacylation and editing domains of leucyl-tRNA synthetase is crucial for its synthetic activity |
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| Authors: | Qian Huang Xiao-Long Zhou Qin-Hua Hu Hui-Yan Lei Zhi-Peng Fang Peng Yao En-Duo Wang |
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| Institution: | 1.Center for RNA Research, State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Shanghai 200031, China;2.School of Life Science and Technology, ShanghaiTech University, Shanghai 200031, China |
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| Abstract: | Leucyl-tRNA synthetases (LeuRSs) catalyze the linkage of leucine with tRNALeu. LeuRS contains a catalysis domain (aminoacylation) and a CP1 domain (editing). CP1 is inserted 35 Å from the aminoacylation domain. Aminoacylation and editing require CP1 to swing to the coordinated conformation. The neck between the CP1 domain and the aminoacylation domain is defined as the CP1 hairpin. The location of the CP1 hairpin suggests a crucial role in the CP1 swing and domain–domain interaction. Here, the CP1 hairpin of Homo sapiens cytoplasmic LeuRS (hcLeuRS) was deleted or substituted by those from other representative species. Lack of a CP1 hairpin led to complete loss of aminoacylation, amino acid activation, and tRNA binding; however, the mutants retained post-transfer editing. Only the CP1 hairpin from Saccharomyces cerevisiae LeuRS (ScLeuRS) could partly rescue the hcLeuRS functions. Further site-directed mutagenesis indicated that the flexibility of small residues and the charge of polar residues in the CP1 hairpin are crucial for the function of LeuRS. |
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| Keywords: | Homo sapiens cytoplasm leucyl-tRNA synthetase CP1 hairpin amino acid activation aminoacylation tRNA binding |
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