Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In response to low (approximately 1 microM) levels of selenium, Escherichia coli synthesizes tRNA(Glu) and tRNA(Lys) species that contain 5-methylaminomethyl-2-selenouridine (mnm5Se2U) instead of 5-methylaminomethyl-2-thiouridine (mnm5S2U). Purified glutamate- and lysine-accepting tRNAs containing either mnm5Se2U (tRNA(SeGlu), tRNA(SeLys] or mnm5S2U (tRNA(SGlu), tRNA(SLys] were prepared by RPC-5 reversed-phase chromatography, affinity chromatography using anti-AMP antibodies and DEAE-5PW ion-exchange HPLC. Since mnm5Se2U, like mnm5S2U, appears to occupy the wobble position of the anticodon, the recognition of glutamate codons (GAA and GAG) and lysine codons (AAA and AAG) was studied. While tRNA(SGlu) greatly preferred GAA over GAG, tRNA(SeGlu) showed less preference. Similarly, tRNA(SGlu) preferred AAA over AAG, while tRNA(SeLys) did not. In a wheat germ extract--rabbit globin mRNA translation system, incorporation of lysine and glutamate into protein was generally greater when added as aminoacylated tRNA(Se) than as aminoacylated tRNA(S). In globin mRNA the glutamate and lysine codons GAG and AAG are more numerous than GAA and AAA, thus a more efficient translation of globin message with tRNA(Se) might be expected because of facilitated recognition of codons ending in G.
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PMID:Selenium-containing tRNA(Glu) and tRNA(Lys) from Escherichia coli: purification, codon specificity and translational activity. 267 51

Eleven isoaccepting lysine tRNAs from mammalian sources are demonstrable by RPC-5 chromatography and polyacrylamide gel electrophoresis. The appearance and amounts of these isoacceptors varies with the source and growth state of cells. One isoacceptor, tRNALys6, observed in preparations of tRNA from some virus-transformed cells in culture, has been characterized by determining functional properties, cellular location, and its nucleotide sequence. tRNALys6 responds primarily to the lysine codon AAA, but it is not used efficiently in a wheat germ translational system in vitro. Compared with lysine isoacceptors 1, 2, 4, 5a, and 5, [3H]lysine appears in vivo in tRNALys6 with a delay of about 3 h. This delay may in part be a result of a less functional tRNA, but a compartmented state of tRNALys6 also appears to be important. tRNALys6 is associated with mitoplasts prepared from KA31 fibroblasts. The nucleotide sequence of tRNALys6 was determined by rapid postlabeling procedures involving limited hydrolysis in formamide, 32P-labeling of 5' ends of fragments with polynucleotide kinase, separation of the nested set of fragments in polyacrylamide denaturing gels, release of 5'-labeled nucleotides with RNase T2, and identification of the released nucleotides by chromatography on PEI cellulose. Confirmation of the positions of major nucleotides was done by using limited digestions by RNases of tRNALys6 labeled with 32P on the 3' terminus in a gel readout procedure. The nucleotide sequence of tRNALys6 differs from that of cytoplasmic lysine tRNAs and mammalian mitochondrial lysine tRNAs. It contains U*, an unidentified modified uridine occurring in the anticodon of some mitochondrial tRNAs. tRNALys6 appears to occur in very limited amounts, or not at all, in most cells unless stressed, but when present it is associated with mitochondria, although it is probably coded in the nucleus.
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PMID:Perturbation of the mitochondrial lysine tRNA population by virus-induced transformation or stress of mammalian cells: functional properties and nucleotide sequence of a mitochondrially associated lysine tRNA. 634 72

Isoaccepting lysyl-tRNAs from virus-transformed cells in culture were fractionated in the RPC-5 system into peaks 1, 2, 4, 5a, 5, and 6. tRNALys6 previously was found predominantly associated with transformed cells. The codon response of each peak was determined in an E. coli ribosomal binding assay. tRNALys1, tRNALys2, and tRNALys4 are highly specific for the 5'AAG3' codon. tRNALys5 and tRNALys5a preferentially bind in response to AAA. tRNALys6 binds in response to AAA 3-fold better than in response to AAG. The presence of thiolated nucleosides in the anticodon regions of tRNALys5a, tRNALys5, and tRNALys6 is indicated by I2-inactivation of aminoacylation ability with no effect on the other is isoacceptors. Functional abilities of the isoacceptors were compared in a wheat germ translational system with tobacco mosaic virus RNA as messenger. All of the isoacceptors function about equally well in translation except for tRNALys6, which is only 14 to 24% as effective as the other isoacceptors.
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PMID:Codon binding and translational properties of an isoaccepting lysine tRNA peculiar to virus-transformed Cells. 680 26