Biomaterial Database

Role of the CCA terminal sequence of tRNA(Val) in aminoacylation with valyl-tRNA synthetase. 1994

K Tamura, and N Nameki, and T Hasegawa, and M Shimizu, and H Himeno

Institute of Space and Astronautical Science, Kanagawa, Japan.

All known tRNAs have a universal CCA sequence at the 3'-terminal. To study the role of this terminal sequence in the aminoacylation process, base substitutions were introduced into a transcript of Escherichia coli valine tRNA and the effects on the aminoacylation activity with valyl-tRNA synthetase were evaluated. Substitution of the terminal adenosine residue at position 76 by C or U caused a 5-7-fold decrease of valine charging activity in Vmax/Km, while substitution by G resulted in about a 300-fold decrease. In addition, these mutations gave rise to an appreciable level of misaminoacylation with threonine. ATP hydrolysis activity during threonylation was lower in the terminal adenosine mutants than in the wild-type. Mutations introduced at positions 75 and 74 also caused threonylation instead of reducing valylation, albeit to a much smaller extent. These results indicate that the CCA sequence, especially the base portion of the terminal adenosine residue, plays an important role not only in amino-acylation efficiency with valine but also in preventing misaminoacylation by hydrolyzing misactivated threonyl-tRNA(Val).

UI	MeSH Term	Description	Entries
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
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.
D000249	Adenosine Monophosphate	Adenine nucleotide containing one phosphate group esterified to the sugar moiety in the 2'-, 3'-, or 5'-position.	AMP,Adenylic Acid,2'-AMP,2'-Adenosine Monophosphate,2'-Adenylic Acid,5'-Adenylic Acid,Adenosine 2'-Phosphate,Adenosine 3'-Phosphate,Adenosine 5'-Phosphate,Adenosine Phosphate Dipotassium,Adenosine Phosphate Disodium,Phosphaden,2' Adenosine Monophosphate,2' Adenylic Acid,5' Adenylic Acid,5'-Phosphate, Adenosine,Acid, 2'-Adenylic,Acid, 5'-Adenylic,Adenosine 2' Phosphate,Adenosine 3' Phosphate,Adenosine 5' Phosphate,Dipotassium, Adenosine Phosphate,Disodium, Adenosine Phosphate,Monophosphate, 2'-Adenosine,Phosphate Dipotassium, Adenosine,Phosphate Disodium, Adenosine
D000586	Amination	The creation of an amine. It can be produced by the addition of an amino group to an organic compound or reduction of a nitro group.	Aminations
D012366	RNA, Transfer, Val	A transfer RNA which is specific for carrying valine to sites on the ribosomes in preparation for protein synthesis.	Transfer RNA, Val,Valine-Specific tRNA,tRNAVal,tRNA(Val),RNA, Val Transfer,Val Transfer RNA,Valine Specific tRNA,tRNA, Valine-Specific
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
D014637	Valine-tRNA Ligase	An enzyme that activates valine with its specific transfer RNA. EC 6.1.1.9	Valyl T RNA Synthetase,Val-tRNA Ligase,Valyl-tRNA Synthetase,Ligase, Val-tRNA,Ligase, Valine-tRNA,Synthetase, Valyl-tRNA,Val tRNA Ligase,Valine tRNA Ligase,Valyl tRNA Synthetase