Toward the full set of human mitochondrial aminoacyl-tRNA synthetases: characterization of AspRS and TyrRS.
The human mitochondrion possesses a translational machinery devoted to the synthesis of 13 proteins. While the required tRNAs and rRNAs are produced by transcription of the mitochondrial genome, all other factors needed for protein synthesis are synthesized in the cytosol and imported. This is the case for aminoacyl-tRNA synthetases, the enzymes which esterify their cognate tRNA with the specific amino acid. The genes for the full set of cytosolic aaRSs are well defined, but only nine genes for mitochondrial synthetases are known. Here we describe the genes for human mitochondrial aspartyl- and tyrosyl-tRNA synthetases and the initial characterization of the enzymes. Both belong to the expected class of synthetases, have a dimeric organization, and aminoacylate Escherichia coli tRNAs as well as in vitro transcribed human mitochondrial tRNAs. Genes for the remaining missing synthetases were also found with the exception of glutaminyl-tRNA synthetase. Their sequence analysis confirms and further extends the view that, except for lysyl- and glycyl-tRNA synthetases, human mitochondrial and cytosolic enzymes are coded by two different sets of genes.
Bonnefond
Luc
L
Department Mécanismes et Macromolécules de la Synthèse Protéique et Cristallogenèse, UPR 9002, Institut de Biologie Moléculaire et Cellulaire du CNRS, 15 rue René Descartes, F-67084 Strasbourg Cedex, France.
Fender
Aurélie
A
Rudinger-Thirion
Joëlle
J
Giegé
Richard
R
Florentz
Catherine
C
Sissler
Marie
M
D000595:Amino Acid Sequence; D001226:Aspartate-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D001483:Base Sequence; D003001:Cloning, Molecular; D019295:Computational Biology / Q000379:methods; D030561:Databases, Nucleic Acid; D006801:Humans; D008928:Mitochondria / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D012349:RNA, Transfer, Asp / Q000378:metabolism; D012365:RNA, Transfer, Tyr / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D046249:Transfer RNA Aminoacylation; D014448:Tyrosine-tRNA Ligase / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification
D012349:RNA, Transfer, Asp; D012365:RNA, Transfer, Tyr; D011994:Recombinant Proteins; D014448:Tyrosine-tRNA Ligase; D001226:Aspartate-tRNA Ligase