Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Transfer RNA Aminoacylation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1976

Transfer RNA and aminoacyl transfer RNA in developing rats.

The total transfer RNA (tRNA) level in the liver, kidney, skeletal muscle and heart muscle of developing rats was determined by purification using (3H)tRNA as an internal standard. Liver and kidney contained almost twice as much tRNA per gram tissue as heart and skeletal muscle. There were no apparent differences between the sexes. The aminoacylation capacities of six tRNA species (alanyl, aspartyl, leucyl, methionyl, phenylalanyl, and tryptophanyl) from rat liver were not different during 3 developmental stages (suckling, weaning and young adult), and there were also no differences noted between males females. The in vivo percent aminoacylation of 4 tRNAs (aspartyl, leucyl, methionyl, and phenylalanyl) was lower during the newborn and suckling periods than in weaning and young adult rat livers. The tRNA of young adults was almost completely aminoacylated in vivo with the exception of alanyl-tRNA.

Acylation↗
PubMed1976

Aminoacyl transfer RNA formation. Binding of cations to transfer RNA and its role in aminoacyl transfer RNA formation.

The role of cations (polyamines and Mg2+) in isoleucyl-tRNA formation catalyzed by purified isolecuyl-tRNA synthetase [EC 6.1.1.5] from Escherichia coli was studied. It was found that spermine, spermidine, and Mg2+ bind to tRNA and that when bound to these cations, tRNA acts as substrate of aminoacylation without requiring further cations. These findings suggest that the primary function of cations in aminoacyl-tRNA formation is to bind to tRNA to stabilize its structure, not to bind to the enzyme to activate it.

Binding Sites↗
PubMed1983

The role of zinc in 5',5'-diadenosine tetraphosphate production by aminoacyl-transfer RNA synthetases.

Aminoacyl-tRNA synthetases are capable of converting 5'-ATP into 5',5'-diadenosine tetraphosphate. The reaction reflects the reversal of enzyme-bound aminoacyl-adenylate by ATP instead of PPi. In the case of a few prokaryotic as well as eukaryotic aminoacyl-tRNA synthetases, the initial rate of diadenosine tetraphosphate synthesis can be greatly enhanced upon adding small amounts of zinc. This observation enables us to establish a relationship between diadenosine tetraphosphate, a nucleotide possibly involved in controlling cell proliferation, and a metallic cofactor, which is believed to play a role in tumour growth.

Adenine Nucleotides↗
PubMed1976

Aminoacyl transfer RNA formation. VII. Lack of correlation between aminoacylation and PPi-ATP exchange catalyzed by isoleucyl-tRNA synthetase of Escherichia coli in the presence of various divalent cations.

Isoleucyl-tRNA formation and isoleucine-dependent PPi-ATP exchange catalyzed by purified isoleucyl-tRNA synthetase [EC 6.1.1.5] of Escherichia coli were studied in the presence of various amounts of either Mg2+, Ca2+, Fe2+, Ni2+, or Cu2+. In the presence of Mg2+, isoleucine-dependent PPi-ATP exchange was observed in parallel with isoleucyl-tRNA formation, while in the presence of Ca2+, isoleucyl-tRNA formation was observed without isoleucine-dependent PPi-ATP exchange. Moreover, isoleucine-dependent PPi-ATP exchange was much more in the presence of Fe2+ than in the presence of Mg2+, while little isoleucyl-tRNA was formed in the presence of Fe2+. In the presence of Ni2+ or Cu2+, neither reaction was observed. These data, indicating that formation of an isoleucyl-AMP-enzyme complex is not a necessary step in isoleucyl-tRNA formation, support the existence of a concerted mechanism of isoleucyl-tRNA formation in E. coli.

Adenosine Triphosphate↗
PubMed1991

Characteristics of a leucine aminoacyl transfer RNA synthetase from Tritrichomonas augusta.

This study has investigated the characteristics of a leucine aminoacyl transfer RNA synthetase enzyme from Tritrichomonas augusta. Differential centrifugation and DEAE-cellulose column chromatography were used for partial enzyme purification. The column purification increased the synthetase activity 125-fold over the unfractionated cell extract. The conditions for maximum [3H] leucine charging were 37 degrees C for 20 min, with protein at 180 micrograms ml-1 using yeast leucine tRNA as an acceptor. The optimal reaction conditions were 14 mM-Mg acetate, 3 mM-ATP, 3 mM-spermidine and 5.5 mM-putrescine. Acceptor activity with T. augusta transfer RNA was 8-fold higher than with yeast transfer RNA and 25-fold higher than with Escherichia coli transfer RNA. The partially purified enzyme fraction had comparable changing activities for both leucine and valine.

Amino Acyl-tRNA Synthetases↗
PubMed1984

Specific sequence homology and three-dimensional structure of an aminoacyl transfer RNA synthetase.

Few and limited amino acid sequence homologies have been found among eight bacterial aminoacyl transfer RNA (tRNA) synthetases whose primary structures are known. The entire 939-amino acid primary structure of Escherichia coli isoleucyl-tRNA synthetase is now reported. In a sequence of 11 consecutive amino acids matching a sequence in E. coli methionyl-tRNA synthetase, there are ten identical residues and one conservative change. This is the strongest homology recorded between any two aminoacyl tRNA synthetases. This part of the methionine enzyme's three-dimensional structure has been determined, and it occurs in a mononucleotide binding fold; a close three-dimensional structural homology of this part of the enzyme with Bacillus stearothermophilus tyrosyl-tRNA synthetase has also been reported. The three synthetases probably fold identically in this region.

Amino Acid Sequence↗
PubMed1990

Autoantibodies to aminoacyl-transfer RNA synthetases for isoleucine and glycine. Two additional synthetases are antigenic in myositis.

Autoantibodies to three of the aminoacyl-transfer RNA (tRNA) synthetases have been reported (for histidine, threonine, and alanine). Most patients with these autoantibodies have polymyositis, and the majority also have interstitial lung disease. This study examined the question of whether autoantibodies to other aminoacyl-tRNA synthetases occur in the sera of myositis patients. We tested sera from patients with myositis with unidentified anticytoplasmic antibodies that immunoprecipitate tRNA for the ability to inhibit the aminoacyl-tRNA synthetases for the remaining 17 amino acids. Three sera showed strong inhibitory activity for a synthetase. OJ and NJ sera (and IgG) significantly inhibited isoleucyl-tRNA synthetase activity, each with 94% inhibition at the screening dilution, whereas other test sera and controls all inhibited less than 50%. OJ and NJ sera immunoprecipitated identical patterns of tRNA, and identical, complex patterns of high m.w. polypeptides that were consistent with the multienzyme synthetase complex of which isoleucyl-tRNA synthetase is a part. EJ serum (and IgG) significantly inhibited glycyl-tRNA synthetase, and immunoprecipitated a unique pattern of transfer RNA, and a strong predominant protein band of 77 kDa. These data strongly suggest that OJ and NJ have autoantibodies to isoleucyl-tRNA synthetase, and that EJ has antibodies to glycyl-tRNA synthetase. The findings of signs of muscle involvement in all three patients, and severe interstitial lung disease in OJ, strengthens the association of antisynthetases with these conditions.

Amino Acyl-tRNA Synthetases↗
PubMed1982

Identification of a selenocysteine-specific aminoacyl transfer RNA from rat liver.

The aminoacylation of rat liver tRNA with selenocysteine was studied in tissue slices and in a cell-free system with [75Se]selenocysteine and [75Se]selenite as substrates. [75Se]Selenocysteyl tRNA was isolated via phenol extraction, 1 M NaCl extraction and chromatography on DEAE-cellulose. [75Se]Selenocysteyl tRNA was purified on columns of DEAE-Sephacel, benzoylated DEAE-cellulose and Sepharose 4B. In a dual-label aminoacylation with [35S]cysteine, the most highly purified 75Se-fractions were greater than 100-fold purified relative to 35S. These fractions contained less than 0.7% of the [35S]cysteine originally present in the total tRNA. When [35Se]selenocysteyl tRNA was purified from a mixture of 14C-labeled amino acids, over 97% of the [14C]aminoacyl tRNA was removed. The [75Se]selenocysteine was associated with the tRNA via an aminoacyl linkage. Criteria used for identification included alkaline hydrolysis and recovery of [75Se]selenocysteine, reaction with hydroxylamine and recovery of [75Se]selenocysteyl hydroxamic acid and release of 75Se by ribonuclease. The specificity of [75Se]selenocysteine aminoacylation was demonstrated by resistance to competition by a 125-fold molar excess of either unlabeled cysteine or a mixture of the other 19 amino acids in the cell-free selenocysteine aminoacylation system.

Animals↗
PubMed1979

Recent results on how aminoacyl transfer RNA synthetases recognize specific transfer RNAs.

Aminoacyl tRNA synthetases discriminate between tRNA species by a highly specific mechanism. Physical and chemical studies indicate that the synthetases bind along and around the inside of the three-dimensional L-shaped tRNA structure. Studies of mutant tRNAs that affect synthetase interaction tend to confirm this conclusion. However, in contrast to proteins that recognize a specific block of contiguous nucleotide units (e.g., repressors, restriction enzymes, etc.), synthetases appear to interact with spatially disperse elements of the structure. Available evidence suggests that tRNA binding clefts on various synthetases may be roughly similar, with specificity being achieved by the choice of amino acid residues in a few critical positions in the tRNA binding clefts. With this idea in mind, it should be possible to introduce amino acid substitutions into the binding clefts and thereby change tRNA recognition specificity. This has been attempted (by genetic manipulations) and a mutant alanine tRNA synthetase with altered tRNA recognition has been isolated. This enzyme can attach alanine to isoleucine specific tRNA. When presented with valine specific tRNA, a tRNA similar in some structural features to the isoleucine specific tRNA, or with the structurally quite different tyrosine specific tRNA, no significant aminoacylation occurs. Thus, a precise specificity alteration can occur through mutation; this result supports the idea of similarities in synthetase binding clefts, with specificity being achieved by the positioning of amino acids at critical positions in these clefts. Finally, further data have been obtained on the issue of possible transient covalent bond formation between synthetases and tRNAs, as a critical part of the interaction.

Amino Acyl-tRNA Synthetases↗