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tRNA-ribosome inter...
tRNA-ribosome interactions
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- Ehrenberg, Måns (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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- Bilgin, Neş’e (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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- Dincbas, Vildan (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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- Karimi, Reza (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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- Hughes, Diarmaid, 1956- (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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- Abdulkarim, Farhad (författare)
- Uppsala universitet,Institutionen för molekylärbiologi
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(creator_code:org_t)
- 1995
- 1995
- Engelska.
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Ingår i: Biochemistry and Cell Biology. - 0829-8211 .- 1208-6002. ; 73:11-12, s. 1049-1054
- Relaterad länk:
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http://www.nrcresear...
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https://urn.kb.se/re...
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Abstract
Ämnesord
Stäng
- Direct measurements of the rates of dissociation of dipeptidyl-tRNA from the ribosome show that hyperaccurate SmP and SmD ribosomes have unstable A-site binding of peptidyl-tRNA, while P-site binding is extremely stable in relation to the wild type. Error-prone Ram ribosomes, on the other hand, have stable A-site and unstable P-site binding of peptidyl-tRNA. At least for these mutant ribosomes, we conclude that stabilization of peptidyl-tRNA in one site destabilizes binding in the other. Elongation factor Tu (EF-Tu) undergoes a dramatic structural transition from its GDP-bound form to its active GTP-bound form, in which it binds aa-tRNA (aminoacyl-tRNA) in ternary complex. The effects of substitution mutations at three sites in domain I of EF-Tu, Gln124, Leu120, and Tyr160, all of which point into the domain I-domain III interface in both the GTP and GDP conformations of EF-Tu, were examined. Mutations at each position cause large reductions in aa-tRNA binding. An attractive possibility is that the mutations alter the domain I-domain III interface such that the switching of EF-Tu between different conformations is altered, decreasing the probability of aa-tRNA binding. We have previously found that two GTPs are hydrolyzed per peptide bond on EF-Tu, the implication being that two molecules of EF-Tu may interact on the ribosome to catalyze the binding of a single aa-tRNA to the A-site. More recently we found that ribosomes programmed with mRNA constructs other than poly(U), including the sequence AUGUUUACG, invariably use two GTPs per peptide bond in EF-Tu function. Other experiments measuring the protection of aa-tRNA from deacylation or from RNAse A attack show that protection requires two molecules of EF-Tu, suggesting an extended ternary complex. To remove remaining ambiguities in the interpretion of these experiments, we are making direct molecular weight determinations with neutron scattering and sedimentation-diffusion techniques.
Nyckelord
- bacterial protein
- bacterial RNA
- elongation factor Tu
- transfer RNA
- genetic selection
- metabolism
- molecular genetics
- nucleotide sequence
- reproducibility
- review
- ribosome
- NATURAL SCIENCES
- NATURVETENSKAP
Publikations- och innehållstyp
- ref (ämneskategori)
- for (ämneskategori)
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