title: Reduction of mitochondrial tRNALeu(UUR) aminoacylation by some MELAS-associated mutations.
abstract: The mitochondrial myopathy, encephalopathy, lactic acidosis and stroke-like episodes syndrome (MELAS) is a rare congenital disorder of mitochondrial DNA. Five single nucleotide substitutions within the human mitochondrial tRNALeu(UUR) gene have been reported to be associated with MELAS. Here, we provide in vitro evidence that the aminoacylation capacities of these five hmtRNALeu(UUR) transcripts are reduced to different extents relative to the wild-type hmtRNALeu(UUR) transcript. A thermal denaturation experiment showed that the A3243G and T3291C mutants, which were the least charged by LeuRS, have fragile structures. In addition, the T3291C mutant can inhibit aminoacylation of the wild-type hmtRNALeu(UUR), indicating that it may act as an inhibitor in the mitochondrial heteroplasmic environment.
authors.affiliation: State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Hao
authors.forename: Yong-Neng
authors.initials: YN
authors.lastname: Yao
authors.forename: Yong-Gang
authors.initials: YG
authors.lastname: Zheng
authors.forename: Min-Gang
authors.initials: MG
authors.lastname: Xu
authors.forename: En-Duo
authors.initials: ED
authors.lastname: Wang
mesh_terms: D049148:Aminoacylation; D001483:Base Sequence; D004272:DNA, Mitochondrial; D006358:Hot Temperature; D006801:Humans; D017241:MELAS Syndrome / Q000235:genetics*; D008928:Mitochondria / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010084:Oxidation-Reduction; D017354:Point Mutation; D011489:Protein Denaturation; D012356:RNA, Transfer, Leu / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D004272:DNA, Mitochondrial; D012356:RNA, Transfer, Leu