Biomaterial Database

The stereochemical course of amino acid activation by methionyl- and tyrosyl-tRNA synthetases. 1979

S P Langdon, and G Lowe

Stereochemical analysis has long been recognised as a powerful tool for elucidating the mechanisms of chemical and enzyme-catalysed reactions. Although much is known about the stereochemical course of reactions at saturated carbon, phosphate and thiophosphate esters whose ligands to phosphorus are also tetrahedrally disposed, are capable in principle of revealing sterochemical information about events at the active site of enzymes that transform such substrates. Nucleotidyl transferases are a group of enzymes which in general selectively use one of the diastereoisomers of a nucleoside 5'(1-thiotriphosphate), such as isomers A and B of adenosine 5'(1-thiotriphosphate), designated ATP alpha S-A and ATP alpha S-B, and allow investigation of the stereochemical course of nucleotidyl transfer. We have developed a simple method based on 31P nuclear magnetic resonance spectroscopy for determining the stereochemical course of these reactions, and using this method show here that the nucleotidyl transfer step in two aminoacyl-tRNA synthetases from Escherichia coli occurs with inversion of configuration at phosphorus. These observations greatly constrain the mechanistic possibilities for these enzymes, and are interpreted most simply as a direct 'in line' transfer from ATP to the amino acid.

UI	MeSH Term	Description	Entries
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
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
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
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
D013237	Stereoisomerism	The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)	Molecular Stereochemistry,Stereoisomers,Stereochemistry, Molecular,Stereoisomer
D014448	Tyrosine-tRNA Ligase	An enzyme that activates tyrosine with its specific transfer RNA. EC 6.1.1.1.	Tyrosyl T RNA Synthetase,Tyr-tRNA Ligase,Tyrosyl-tRNA Synthetase,Ligase, Tyr-tRNA,Ligase, Tyrosine-tRNA,Synthetase, Tyrosyl-tRNA,Tyr tRNA Ligase,Tyrosine tRNA Ligase,Tyrosyl tRNA Synthetase
D046249	Transfer RNA Aminoacylation	The conversion of uncharged TRANSFER RNA to AMINO ACYL TRNA.	Aminoacylation, Transfer RNA,Transfer RNA Charging,tRNA Aminoacylation,tRNA Charging,Amino Acid Activation, Translational,Transfer RNA Acylation,Transfer RNA Amino Acylation,tRNA Acylation,tRNA Amino Acylation,Acylation, Transfer RNA,Acylation, tRNA,Acylations, Transfer RNA,Acylations, tRNA,Amino Acylation, tRNA,Aminoacylation, tRNA,Aminoacylations, Transfer RNA,Aminoacylations, tRNA,RNA Aminoacylations, Transfer,RNA Charging, Transfer,Transfer RNA Acylations,Transfer RNA Aminoacylations,Transfer RNA Chargings,tRNA Acylations,tRNA Aminoacylations,tRNA Chargings