アミノアシルtRNA
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出典(authority):フリー百科事典『ウィキペディア(Wikipedia)』「2015/11/22 18:34:35」(JST)
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Aminoacyl-tRNA (also aa-tRNA or charged tRNA) is tRNA to which its cognated amino acid is chemically bonded (charged). The aa-tRNA, along with some elongation factors, deliver the amino acid to the ribosome for incorporation into the polypeptide chain that is being produced.[1] A specific cognate amino acid is charged or aminoacylated to each tRNA by aminoacyl tRNA synthetase. This matching is crucial, since it ensures that only the particular amino acid matching the anticodon of the tRNA, and in turn matching the codon of the mRNA, is used in protein synthesis.
Due to the degeneracy of the genetic code, multiple tRNAs will have the same amino acid but different codons. These different tRNAs are called isoacceptors. Under certain circumstances, non-cognate amino acids will be charged, resulting in mischarged or misaminoacylated tRNA. These mischarged tRNAs must be hydrolyzed in order to prevent incorrect protein synthesis.
Contents
- 1 Synthesis
- 2 Hydrolysis
- 3 Drug targeting
- 4 References
- 5 See also
Synthesis
Aminoacyl-tRNA is produced in two steps. First is the adenylation of the amino acid, which forms aminoacyl-AMP:
- amino acid + ATP ↔ aminoacyl-AMP + PPi
Second, the amino acid residue is transferred to the tRNA:
- aminoacyl-AMP + tRNA ↔ aminoacyl-tRNA + AMP
The net reaction is:
- amino acid + ATP + tRNA ↔ aminoacyl-tRNA + AMP + PPi
The net reaction is energetically favourable only because the pyrophosphate is hydrolysed; that reaction is highly energetically favourable and drives the other reactions. All of these reactions take place inside the aminoacyl-tRNA synthetase specific for that tRNA.
Hydrolysis
The different aa-tRNAs have varying pseudo-first-order rate constants for the hydrolysis of the ester bond between amino acid and tRNA.[2] In general, proline aa-tRNA is found to be the least stable while the steric hindrance of the methyl group on the β carbon of isoleucine and valine tend to stabilize their aa-tRNAs. Increased ionic strength resulting from sodium, potassium, and magnesium salts has been shown to destabilize the aa-tRNA bond. Increased pH also destabilizes the bond and changes the ionization of the α carbon amino group of the amino acid. The charged amino group can destabilize the aa-tRNA bond via the inductive effect. The elongation factor EF-Tu has been shown to stabilize the bond.[3]
Drug targeting
Certain drugs like tetracycline prevent the aminoacyl-tRNA from binding to the ribosomal subunit in prokaryotes.
References
- ^ Berg J, Tymoczko JL, Stryer L (2006). Biochemistry (6th ed. ed.). San Francisco: W. H. Freeman. ISBN 0-7167-8724-5.
- ^ Hentzen, Daniele; et al. (1972). "Relation between aminoacyl-tRNA stability and the fixed amino acid". Biochmica et Biophysica Acta 281: 228–232. doi:10.1016/0005-2787(72)90174-8.
- ^ Pinck, M; Francis S (1974). "On the chemical reactivity of aminoacyl-tRNA ester bond I, II, III". Biochimie 56: 383–390. doi:10.1016/s0300-9084(74)80146-x.
See also
- Aminoacyl tRNA synthetase
UpToDate Contents
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English Journal
- Rapid detection of exon 2-deleted AIMP2 mutation as a potential biomarker for lung cancer by molecular beacons.
- Jo SM, Kim Y, Jeong YS, Hee Oh Y, Park K, Kim HS.SourceDepartment of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea.
- Biosensors & bioelectronics.Biosens Bioelectron.2013 Aug 15;46:142-9. doi: 10.1016/j.bios.2013.02.037. Epub 2013 Mar 6.
- Exon 2 deletion in aminoacyl tRNA synthetase complex-interacting multifunctional protein 2 (AIMP2) has been suggested to be associated with the progression of various cancers such as lung and ovarian cancers. However, few studies have been conducted regarding detection and relevance of exon 2-delete
- PMID 23537880
- The Structure of FemXWv in Complex with a Peptidyl-RNA Conjugate: Mechanism of Aminoacyl Transfer from Ala-tRNA(Ala) to Peptidoglycan Precursors.
- Fonvielle M, Li de La Sierra-Gallay I, El-Sagheer AH, Lecerf M, Patin D, Mellal D, Mayer C, Blanot D, Gale N, Brown T, van Tilbeurgh H, Ethève-Quelquejeu M, Arthur M.SourceLaboratoire de Recherche Moléculaire sur les Antibiotiques, Centre de Recherche des Cordeliers, Equipe 12, INSERM, U872, 75006 Paris (France); Université Pierre et Marie Curie - Paris 6, UMR S 872, 15 rue de l'Ecole de Médecine, 75006 Paris (France); Université Paris Descartes, Sorbonne Paris Cité, UMR S 872, 75006 Paris (France).
- Angewandte Chemie (International ed. in English).Angew Chem Int Ed Engl.2013 Jul 8;52(28):7278-81. doi: 10.1002/anie.201301411. Epub 2013 Jun 6.
- To gain insight into the catalytic mechanism of non-ribosomal amino acid transferases, peptidyl-RNA conjugates were synthesized for co-crystallization with FemXWv of Weissella viridescens, which transfers L-Ala from Ala-tRNA(Ala) to the peptidoglycan precursor UDP-MurNAc-pentapeptide. The structure
- PMID 23744707
- The mechanistic and evolutionary aspects of the 2[prime]- and 3[prime]-OH paradigm in biosynthetic machinery.
- Safro M, Klipcan L.AbstractBACKGROUND: The translation machinery underlies a multitude of biological processes within the cell. The design and implementation of the modern translation apparatus on even the simplest course of action is extremely complex, and involves different RNA and protein factors. According to the "RNA world" idea, the critical link in the translation machinery may be assigned to an adaptor tRNA molecule. Its exceptional functional and structural characteristics are of primary importance in understanding the evolutionary relationships among all these macromolecular components.
- Biology direct.Biol Direct.2013 Jul 8;8(1):17. [Epub ahead of print]
- BACKGROUND: The translation machinery underlies a multitude of biological processes within the cell. The design and implementation of the modern translation apparatus on even the simplest course of action is extremely complex, and involves different RNA and protein factors. According to the "RNA wor
- PMID 23835000
Japanese Journal
- 研究・症例 外科的肺生検で急性肺障害を伴う間質性肺炎を認め,抗ARS抗体陽性であった シェーグレン症候群の1例
- 抗ARS抗体陽性間質性肺炎の病理 (特集 抗アミノアシルtRNA合成酵素抗体と間質性肺炎 : 最近の話題)
- 抗ARS抗体陽性間質性肺炎の画像特徴を探る (特集 抗アミノアシルtRNA合成酵素抗体と間質性肺炎 : 最近の話題)
Related Links
- References for "Aminoacyl tRNA" im Internet, an Universitäten und in der Literatur... cyclopaedia.net ... Horizontal gene transfer (HGT) involves the acquisition of genetic material from a donor organism and its incorporation into the ...
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Related Pictures
★リンクテーブル★
[★]
- 英
- ribosome
- 関
- 細胞
- mRNAを元にアミノ酸を重合してタンパク質を合成する細胞小器官
- rRNAとタンパク質からなる
- HE染色では好酸性に染まる。核酸成分(rRNA)が多いため青染することになる。
- 原核生物:70S = 30Sサブユニット + 50Sサブユニット
- 真核生物:80S = 40Sサブユニット + 60Sサブユニット
タンパク質合成 (ECB.252)
- mRNAの5'側にE部位が位置し、P部位、A部位の順に並んでいる。
- 1. コドンに対応するアミノアシルtRNAがA部位に取り込まれる
- 2. アミノアシルtRNAのアミノ酸に、ペプチジルtRNAに結合しているペプチドが転移される
- リボソームがスライドすることで、ペプチドを渡したtRNAはE部位に、ペプチジルtRNAはP部位に移動する。
- 3. E部位のtRNAはリボソームから遊離する
- 4. 1.へもどる
抗菌薬の作用点
[★]
- 英
- aminoacyl-tRNA, aminoacyl transfer RNA, aa-tRNA
- 同
- アミノアシル運搬RNA
- 関
- ペプチジルtRNA、リボソーム
[★]
アミノアシルtRNA合成酵素、アミノアシルtRNAシンテターゼ、アミノアシルtRNAシンセターゼ
- 関
- amino acyl-tRNA synthetase
[★]
アミノアシルtRNA結合部位
[★]
トランスファーRNA, transfer RNA, 転位RNA
[★]
トランスファーRNA transfer RNAs