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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/07/23 14:06:54」(JST)

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EF-Tu was PDB Molecule of the Month pdb81_1 on September 2006. Blue: EF-Tu, red: tRNA, yellow: GTP.

EF-Tu (elongation factor thermo unstable) is one of the prokaryotic elongation factors. Elongation factors are part of the mechanism that synthesizes new proteins by translation at the ribosome. Individual amino acid links are added to the protein chain by transfer RNA (t-RNA). Messenger RNA (mRNA) carries a codon that codes for each amino acid. t-RNA carries the amino acid and an anticodon for that amino acid. The ribosome creates a protein chain by following the mRNA code and selecting the next t-RNA and its amino acid.

The prokaryotic factor EF-Tu helps the aminoacyl-tRNA move onto a free site on the ribosome. In the cytoplasm, EF-Tu binds an aminoacylated, or charged, tRNA molecule. This complex enters the ribosome.

There are 3 tRNA attachment sites on the ribosome: A, P and E. The tRNA complex first binds to the A site, then moves to the P site, and is released at the E site.

The tRNA anticodon domain associates with the mRNA codon domain in the ribosomal A site. If the codon-anticodon pairing is correct, EF-Tu hydrolyzes guanosine triphosphate (GTP) into guanosine diphosphate (GDP) and inorganic phosphate. This creates a conformational change in EF-Tu that causes EF-Tu to dissociate from the tRNA of the ternary complex (and therefore leave the ribosome). The aminoacyl-tRNA then fully enters the A site, where its amino acid is brought near the P site's polypeptide and the ribosome catalyzes the covalent transfer of the amino acid onto the polypeptide. Finally it moves to the E site and is released.

EF-Tu contributes to translational accuracy in three ways. It delays GTP hydrolysis if the tRNA in the ribosome’s A site does not match the mRNA codon, thus preferentially increasing the likelihood for the incorrect tRNA to leave the ribosome. It also adds a second delay (regardless of tRNA matching) after freeing itself from tRNA, before the aminoacyl-tRNA fully enters the A site. This delay period is a second opportunity for incorrectly paired tRNA (and their bound amino acids) to move out of the A site before the incorrect amino acid is irreversibly added to the polypeptidic chain. A third mechanism is the less well understood function of EF-Tu to crudely check aminoacyl-tRNA associations and reject complexes where the amino acid is not bound to the correct tRNA coding for it.

External links[edit]

Peptide Elongation Factor Tu at the US National Library of Medicine Medical Subject Headings (MeSH)

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English Journal

The Arabidopsis NPK1-related protein kinases ANPs are required for elicitor-induced oxidative burst and immunity.

Savatin DV1, Gigli Bisceglia N, Marti L, Fabbri C, Cervone F, De Lorenzo G.
Plant physiology.Plant Physiol.2014 May 8. [Epub ahead of print]
Plant immunity is activated through complex and cross-talking transduction pathways that include a mitogen-activated protein kinase (MAPK) phosphorylation cascade. Here, we have investigated the role in immunity of the Arabidopsis gene subfamily that encodes the MAP triple kinases indicated as ANP1,
PMID 24812107

Effects of exercise training on depression in patients with heart failure: a systematic review and meta-analysis of randomized controlled trials.

Tu RH1, Zeng ZY, Zhong GQ, Wu WF, Lu YJ, Bo ZD, He Y, Huang WQ, Yao LM.
European journal of heart failure.Eur J Heart Fail.2014 May 2. doi: 10.1002/ejhf.101. [Epub ahead of print]
AIMS: The aim of this review is to assess the effects of exercise training on the symptoms of depression in heart failure (HF) patients.METHODS AND RESULTS: Randomized controlled trials of exercise training in patients with HF and symptoms of depression were identified. The depression data were pool
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A tRNA body with high affinity for EF-Tu hastens ribosomal incorporation of unnatural amino acids.

Ieong KW, Pavlov MY, Kwiatkowski M, Ehrenberg M, Forster AC.
RNA (New York, N.Y.).RNA.2014 May;20(5):632-43. doi: 10.1261/rna.042234.113. Epub 2014 Mar 26.
There is evidence that tRNA bodies have evolved to reduce differences between aminoacyl-tRNAs in their affinity to EF-Tu. Here, we study the kinetics of incorporation of L-amino acids (AAs) Phe, Ala allyl-glycine (aG), methyl-serine (mS), and biotinyl-lysine (bK) using a tRNA(Ala)-based body (tRNA(A
PMID 24671767