Biomaterial Database

Hydrolytic action of aminoacyl-tRNA synthetases from baker's yeast. "Chemical proofreading" of Thr-tRNA Val by valyl-tRNA synthetase studied with modified tRNA Val and amino acid analogues. 1977

G L Igloi, and F von der Haar, and F Cramer

The properties of native and of two modified tRNA Val species in the correction of misactivated threonine by valyl-tRNA synthetase have been studied. Whereas Thr-tRNA Val-C-C-A could not be isolated in the valyl-tRNA synthetase catalyzed reaction, Thr-tRNA Val-C-C-3'dA is isolable in up to 50% yield in this system and tRNA Val-C-C-3'NH2A is fully aminoacylated with threonine by the same enzyme. The hydrolysis of preformed Thr-tRNA Val-C-C-A by free valyl-tRNA synthetase is 30 times faster than the corresponding breakdown of Val-tRNA Val-C-C-A. This hydrolytic activity is also observed with Thr-tRNA Val-C-C-3'dA although the rate is reduce to that of the reaction of Val-tRNA Val-C-C-A. Modification of the threonine to O-methylthreonine, which is also a substrate for valyl-tRNA synthetase, leads to stabilization of the O-methylthreonyl-tRNA esters. The AMP/PP independent hydrolysis under aminoacylating conditions, which is a measure of the correction process, indicates that O-MeThr-tRNA Val-C-C-A is only very slowly corrected while the tRNA Val-C-C-3'dA and tRNA Val-C-C-3'NH2A esters are completely stable. Removal of the methoxy group of O-methylthreonine as in alpha-amino-butyric acid increases the rate of the hydrolytic reaction and once again alpha-Abu-tRNA Val-C-C-A and alpha-Abu-tRNA Val-C-C-3'dA are unstable under aminoacylating conditions and not isolable.

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
D007700	Kinetics	The rate dynamics in chemical or physical systems.
D011485	Protein Binding	The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.	Plasma Protein Binding Capacity,Binding, 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
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D012343	RNA, Transfer	The small RNA molecules, 73-80 nucleotides long, that function during translation (TRANSLATION, GENETIC) to align AMINO ACIDS at the RIBOSOMES in a sequence determined by the mRNA (RNA, MESSENGER). There are about 30 different transfer RNAs. Each recognizes a specific CODON set on the mRNA through its own ANTICODON and as aminoacyl tRNAs (RNA, TRANSFER, AMINO ACYL), each carries a specific amino acid to the ribosome to add to the elongating peptide chains.	Suppressor Transfer RNA,Transfer RNA,tRNA,RNA, Transfer, Suppressor,Transfer RNA, Suppressor,RNA, Suppressor Transfer
D012441	Saccharomyces cerevisiae	A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.	Baker's Yeast,Brewer's Yeast,Candida robusta,S. cerevisiae,Saccharomyces capensis,Saccharomyces italicus,Saccharomyces oviformis,Saccharomyces uvarum var. melibiosus,Yeast, Baker's,Yeast, Brewer's,Baker Yeast,S cerevisiae,Baker's Yeasts,Yeast, Baker
D013329	Structure-Activity Relationship	The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.	Relationship, Structure-Activity,Relationships, Structure-Activity,Structure Activity Relationship,Structure-Activity Relationships
D013912	Threonine	An essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins.	L-Threonine,L Threonine
D013914	Threonine-tRNA Ligase	An enzyme that activates threonine with its specific transfer RNA. EC 6.1.1.3.	Threonyl T RNA Synthetase,Thr-tRNA Ligase,Threonyl-tRNA Synthetase,Ligase, Thr-tRNA,Ligase, Threonine-tRNA,Synthetase, Threonyl-tRNA,Thr tRNA Ligase,Threonine tRNA Ligase,Threonyl tRNA Synthetase