Biomaterial Database

Chemical modification and mutagenesis studies on zinc binding of aminoacyl-tRNA synthetases. 1993

O Nureki, and T Kohno, and K Sakamoto, and T Miyazawa, and S Yokoyama

Department of Biophysics and Biochemistry, Faculty of Science, University of Tokyo, Japan.

Thermus thermophilus methionyl-tRNA synthetase consists of two identical subunits with a potential Zn(2+)-binding sequence of Cys-X2-Cys-X13-Cys-X2-His (Nureki, O., Muramatsu, T., Suzuki, K., Kohda, D., Matsuzawa, H., Ohta, T. Miyazawa, T., and Yokoyama, S. (1991) J. Biol. Chem. 266, 3268-3277). Upon chemical modification of the 3 Cys residues of T. thermophilus MetRS with sodium p-(hydroxymercuri)phenylsulfonate, one Zn2+ ion was released from one subunit of the molecule, as monitored with 4-(2-pyridylazo)resorcinol. Site-directed mutagenesis of Cys and His residues in the Zn(2+)-binding sequence reduced the aminoacylation activity; the kcat value was markedly decreased, and the Km values for L-methionine and tRNAf(Met) were increased. Similarly, Cys modification released two Zn2+ ions from T. thermophilus and Escherichia coli isoleucyl-tRNA synthetases and E. coli threonyl-tRNA synthetase, which have Zn(2+)-binding motifs, and impaired their activities. By contrast, three other aminoacyl-tRNA synthetases that lack Zn(2+)-binding motif neither released Zn2+ ion nor lost their activities upon Cys modification. These results indicate that the Zn(2+)-binding sequences are important for catalysis and recognition in the aminoacylation reactions of a subgroup of aminoacyl-tRNA synthetases.

UI	MeSH Term	Description	Entries
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
D010663	Phenylmercury Compounds	Organic mercury compounds in which the mercury is attached to a phenyl group. Often used as fungicides and seed treatment agents.	Phenyl Mercury Compounds,Phenylmercurials,Compounds, Phenyl Mercury,Compounds, Phenylmercury,Mercury Compounds, Phenyl
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
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
D000604	Amino Acyl-tRNA Synthetases	A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.	Amino Acyl T RNA Synthetases,Amino Acyl-tRNA Ligases,Aminoacyl Transfer RNA Synthetase,Aminoacyl-tRNA Synthetase,Transfer RNA Synthetase,tRNA Synthetase,Acyl-tRNA Ligases, Amino,Acyl-tRNA Synthetases, Amino,Amino Acyl tRNA Ligases,Amino Acyl tRNA Synthetases,Aminoacyl tRNA Synthetase,Ligases, Amino Acyl-tRNA,RNA Synthetase, Transfer,Synthetase, Aminoacyl-tRNA,Synthetase, Transfer RNA,Synthetase, tRNA,Synthetases, Amino Acyl-tRNA
D015032	Zinc	A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.
D016296	Mutagenesis	Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.	Mutageneses
D016963	Thermus thermophilus	A species of gram-negative, aerobic, rod-shaped bacteria found in hot springs of neutral to alkaline pH, as well as in hot-water heaters.