Abstract
Elongation factor 2 (EF-2), ADP-ribosylated in vitro by the A-fragment of diphtheria toxin, can (in the presence of GMPPCP) form stable complexes with ribosomes regardless of whether the ribosomes are empty or carrying poly(U) and Phe-tRNA in the A-site. Despite its efficient binding to ribosomes, ADP-ribosyl-EF-2, in contrast to the non-modified EF-2 is unable to promote the shift of Phe-tRNA from the A-site to the P-site of the ribosome as determined by the puromycin reaction, i.e. it is incapable of promoting the translocation reaction within the ribosome.
MeSH terms
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Adenosine Diphosphate Ribose / metabolism*
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Animals
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Binding, Competitive
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Biological Transport
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Diphtheria Toxin / metabolism
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Guanosine Triphosphate / analogs & derivatives
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Guanosine Triphosphate / pharmacology
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Peptide Elongation Factor 2
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Peptide Elongation Factors / metabolism*
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Poly U / metabolism
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Puromycin / metabolism
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RNA, Transfer, Phe / metabolism
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Rabbits
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Ribosomes / metabolism*
Substances
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Diphtheria Toxin
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Peptide Elongation Factor 2
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Peptide Elongation Factors
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RNA, Transfer, Phe
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Adenosine Diphosphate Ribose
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Poly U
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guanosine 5'-(beta,gamma-methylene)triphosphate
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Puromycin
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Guanosine Triphosphate