Biomaterial Database

Homology of yeast mitochondrial leucyl-tRNA synthetase and isoleucyl- and methionyl-tRNA synthetases of Escherichia coli. 1988

A Tzagoloff, and A Akai, and M Kurkulos, and B Repetto

Department of Biological Sciences, Columbia University, New York, New York 10027.

Respiratory deficient mutants of Saccharomyces cerevisiae previously assigned to complementation group G59 are pleiotropically deficient in respiratory chain components and in mitochondrial ATPase. This phenotype has been shown to be a consequence of mutations in a nuclear gene coding for mitochondrial leucyl-tRNA synthetase. The structural gene (MSL1) coding for the mitochondrial enzyme has been cloned by transformation of two different G59 mutants with genomic libraries of wild type yeast nuclear DNA. The cloned gene has been sequenced and shown to code for a protein of 894 residues with a molecular weight of 101,936. The amino-terminal sequence (30-40 residues) has a large percentage of basic and hydroxylated residues suggestive of a mitochondrial import signal. The cloned MSL1 gene was used to construct a strain in which 1 kb of the coding sequence was deleted and substituted with the yeast LEU2 gene. Mitochondrial extracts obtained from the mutant carrying the disrupted MSL1::LEU2 allele did not catalyze acylation of mitochondrial leucyl-tRNA even though other tRNAs were normally charged. These results confirmed the correct identification of MSL1 as the structural gene for mitochondrial leucyl-tRNA synthetase. Mutations in MSL1 affect the ability of yeast to grow on nonfermentable substrates but are not lethal indicating that the cytoplasmic leucyl-tRNA synthetase is encoded by a different gene. The primary sequence of yeast mitochondrial leucyl-tRNA synthetase has been compared to other bacterial and eukaryotic synthetases. Significant homology has been found between the yeast enzyme and the methionyl- and isoleucyl-tRNA synthetases of Escherichia coli. The most striking primary sequence homology occurs in the amino-terminal regions of the three proteins encompassing some 150 residues. Several smaller domains in the more internal regions of the polypeptide chains, however, also exhibit homology. These observations have been interpreted to indicate that the three synthetases may represent a related subset of enzymes originating from a common ancestral gene.

UI	MeSH Term	Description	Entries
D007533	Isoleucine-tRNA Ligase	An enzyme that activates isoleucine with its specific transfer RNA. EC 6.1.1.5.	Isoleucyl T RNA Synthetase,Isoleucyl- tRNA Synthetase ILS1,Isoleucyl-tRNA Synthetase 1,Isoleucyl-tRNA Synthetase ILES1,Ile-tRNA Ligase,Isoleucyl-tRNA Synthetase,1, Isoleucyl-tRNA Synthetase,ILES1, Isoleucyl-tRNA Synthetase,Ile tRNA Ligase,Isoleucine tRNA Ligase,Isoleucyl tRNA Synthetase,Isoleucyl tRNA Synthetase 1,Isoleucyl tRNA Synthetase ILES1,Isoleucyl tRNA Synthetase ILS1,Ligase, Ile-tRNA,Ligase, Isoleucine-tRNA,Synthetase 1, Isoleucyl-tRNA,Synthetase ILES1, Isoleucyl-tRNA,Synthetase, Isoleucyl-tRNA
D007935	Leucine-tRNA Ligase	An enzyme that activates leucine with its specific transfer RNA. EC 6.1.1.4.	Leucyl T RNA Synthetase,Leu-tRNA Ligase,Leucine-tRNA Synthetase,Leu tRNA Ligase,Leucine tRNA Ligase,Leucine tRNA Synthetase,Ligase, Leu-tRNA,Ligase, Leucine-tRNA,Synthetase, Leucine-tRNA
D008718	Methionine-tRNA Ligase	An enzyme that activates methionine with its specific transfer RNA. EC 6.1.1.10.	Methionyl T RNA Synthetase,Met-tRNA Ligase,Methionyl-tRNA Synthetase,Ligase, Met-tRNA,Ligase, Methionine-tRNA,Met tRNA Ligase,Methionine tRNA Ligase,Methionyl tRNA Synthetase,Synthetase, Methionyl-tRNA
D008969	Molecular Sequence Data	Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.	Sequence Data, Molecular,Molecular Sequencing Data,Data, Molecular Sequence,Data, Molecular Sequencing,Sequencing Data, Molecular
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D004262	DNA Restriction Enzymes	Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.	Restriction Endonucleases,DNA Restriction Enzyme,Restriction Endonuclease,Endonuclease, Restriction,Endonucleases, Restriction,Enzymes, DNA Restriction,Restriction Enzyme, DNA,Restriction Enzymes, DNA
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D005838	Genotype	The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.	Genogroup,Genogroups,Genotypes
D000215	Acylation	The addition of an organic acid radical into a molecule.
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein