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Tiểu luận "Hóa sinh đại cương: Trình bày về tRNA" có nội dung trình bày tổng quan về RNA và tRNA; Nghiên cứu cấu trúc Mononucleotide; Cấu trúc sơ cấp; Cấu trúc thứ cấp; Liên kết với ribosome và tham gia quá trình tổng hợp protein;... Mời các bạn cùng tham khảo chi tiết bài tiểu luận tại đây.

Bài giảng Sinh học phân tử: Các loại ARN - ThS. Nguyễn Thanh Tố Nhi cung cấp cho học viên những kiến thức về khái niệm và vài trò của ARN, các loại ARN: rRNA – ARN ribosom, tRNA – ARN vận chuyển, mRNA – ARN thông tin; quá trình cắt, nối; các snARN và các scARN;... Mời các bạn cùng tham khảo chi tiết nội dung bài giảng!

Cytidine in the anticodon second position (position 35) and G or U in position 36 of tRNAArg are required for aminoacylation by arginyl-tRNA synthetase (ArgRS) from Escherichia coli. Nevertheless, an arginine-accepting amber suppressor tRNA with a CUA anticodon (FTOR1D26) exhibits suppression activity in vivo [McClain, W.H. & Foss, K. (1988) Science, 241, 1804 –1807]. By an in vitro kinetic study with mutagenized tRNAs, we showed that the arginylation of FTOR1D26 involves C34 and U35, and that U35 can be replaced by G without affecting the activity. Thus, the positioning of the essential nucleotides for the arginylation is shifted to the 50...

Multimolecular complexes involving the eukaryotic elongation factor 1A (eEF1A) have been suggested to play an important role in the channeling (vectorial transfer) of tRNAduring protein synthesis [Negrutskii, B.S.&El’skaya, A.V. (1998)Prog. Nucleic Acids Res. Mol. Biol.60,47–78]. Recently we have demonstrated that besides performing its canonical function of forming a ternary complex with GTP and aminoacyl-tRNA, the mammalian eEF1A can produce a noncanonical ternary complex with GDP and uncharged tRNA [Petrushenko, Z.M., Negrutskii, B.S.,...

The ability of aminoacyl-tRNA synthetases to distinguish betweensimilaraminoacidsiscrucial foraccuratetrans-lation of the genetic code. Saccharomyces cerevisiae seryl-tRNA synthetase (SerRS) employs tRNA-dependent recognition of its cognate amino acid serine [Lenhard, B., Filipic, S., Landeka, I., Skrtic, I., So¨ll, D. & Weygand-Durasevic, I. (1997)J. Biol. Chem.272, 1136–1141]. Herewe show that dimeric SerRS enzyme complexed with one molecule of tRNA Ser is more specific and more efficient in catalyzing seryl-adenylate formation than the apoenzyme alone. ...

The interaction of aThermus thermophilustmRNA tran-script with alanyl-tRNA synthetase and elongation factor Tu has been studied. The synthetic tmRNA was found to be stable up to 70
C. The thermal optimum of tmRNA alanylation was determined to be around 50
C. At 50
C, tmRNA transcript was aminoacylated by alanyl-tRNA synthetase with 5.9times lower efficiency (kcat /Km) than tRNA Ala , primarily because of the difference in turnover numbers (kcat ). Studies on EF-Tu protection of Ala
tmRNA against alkaline hydrolysis revealed the existence of at least two different binding sites for EF-Tu on charged tmRNA. ...

InEscherichia colithe codons CGG, AGG, UGG or GGG (NGG codons) but not GGN or GNG (where N is non-G) are associated with low expres-sion of a reporter gene, if located at positions +2 to +5. Induction of a lacZ reporter gene with any one of the NGG codons at position +2 to +5 does not influence growth of a normal strain, but growth of a strain with a defective peptidyl-tRNA hydrolase (Pth) enzyme is inhibited.

Stringent factor is a ribosome-dependent ATP:GTP pyrophosphoryl trans-ferase that synthesizes (p)ppGpp upon nutrient deprivation. It is activated by unacylated tRNA in the ribosomal amino-acyl site (A-site) but it is unclear how activation occurs. A His-tagged stringent factor was isolated by affinity-chromatography and precipitation. This procedure yielded a protein of high purity that displayed (a) a low endogenous pyrophosphoryl transferase activity that was inhibited by the antibiotic tetracycline; ...

In its tRNA acceptor end binding domain, the glutamyl-tRNA synthetase (GluRS) of Escherichia colicontains one atom ofzinc that holds the extremities ofa segment (Cys98-x-Cys100-x24-Cys125-x-His127) homologous to the Escherichia coliglutaminyl-tRNA synthetase (GlnRS) loop where a leucine residue stabilizes the peeled-back conformation of tRNA Gln acceptor end. We report here that the GluRS zinc-binding region belongs to the novel SWIM domain family characterized by the signature C-x-C-xn-C-x-H (n¼6–25),...

The methanogenic archaeaMethanococcus jannaschiiand M. maripaludiscontain an atypical seryl-tRNA synthetase (SerRS), which recognizes eukaryotic and bacterial tRNAs Ser , in addition to the homologous tRNA Ser and tRNA Sec species.The relativeflexibility in tRNArecognition displayed by methanogenic SerRSs, shown by aminoacyla-tion and gel mobility shift assays, indicates the conservation of some serine determinants in all three domains. The complex of M. maripaludisSerRS with the homologues tRNA Ser was isolated by gel filtration chromatography....

We show a simple and reliable method of tRNA aminoacylation with natural, as well as non-natural, amino acids at high pressure. Such specific and noncognate tRNAs can be used as valuable substrates for protein engineering. Aminoacylation yield at high pressure depends on the chem-ical nature of the amino acid used and it is up to 10%.

The seryl-tRNA synthetase fromSaccharomyces cerevisiaeinteracts with the peroxisome biogenesis-related factor Pex21p. Several deletion mutants of seryl-tRNA synthetase were constructed and inspected for their ability to interact with Pex21p in a yeast two-hybrid assay, allowing mapping of the synthetase domain required for complex assembly.

Seryl-tRNA synthetase (SerRS) is a class II aminoacyl-tRNA synthetase that catalyzes serine activation and its transfer to cognate tRNA Ser . Previ-ous biochemical and structural studies have revealed that bacterial- and methanogenic-type SerRSs employ different strategies of substrate recogni-tion.

The initial step of tetrapyrrole biosynthesis inEscherichia coliinvolves the NADPH-dependent reduction by glutamyl-tRNA reductase (GluTR) of tRNA-bound glutamate to glutamate-1-semialdehyde. We evaluated the contribution of the glutamate moiety of glutamyl-tRNA to substrate speci-ficityin vitro using a range of substrates and enzyme variants.

The eukaryotic class 1 polypeptide chain release factor is a three-domain protein involved in the termination of translation, the final stage of poly-peptide biosynthesis. In attempts to understand the roles of the mid-dle domain of the eukaryotic class 1 polypeptide chain release factor in the transduction of the termination signal from the small to the large ribo-somal subunit and in peptidyl-tRNA hydrolysis, its high-resolution NMR structure has been obtained.

l-Canavanine occurs as a toxic non-protein amino acid in more than 1500 leguminous plants. One mechanism of its toxicity is its incorporation into proteins, replacingl-arginine and giving rise to functionally aberrant poly-peptides.

Antigen binding to the B-cell receptor (BCR) of pre-mature B lymphocytes induces their apoptotic cell death, but binding to the BCR of mature B lymphocytes triggers activation and proliferation. Binding to pre-mature B lymphocytes is thought not only to function as a mechanism to exclude B-cell clones that possess the ability to react with self-antigen, but also to act as a defense mechanism in auto-immune diseases.