Role of the individual domains of translation termination factor eRF1 in GTP binding to eRF3 |
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Authors: | Kononenko Artem V Mitkevich Vladimir A Dubovaya Vera I Kolosov Peter M Makarov Alexander A Kisselev Lev L |
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Institution: | Engelhardt Institute of Molecular Biology, The Russian Academy of Sciences, Moscow 119991, Russia. |
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Abstract: | Eukaryotic translational termination is triggered by polypeptide release factors eRF1, eRF3, and one of the three stop codons at the ribosomal A-site. Isothermal titration calorimetry shows that (i) the separated MC, M, and C domains of human eRF1 bind to eRF3; (ii) GTP binding to eRF3 requires complex formation with either the MC or M + C domains; (iii) the M domain interacts with the N and C domains; (iv) the MC domain and Mg2+ induce GTPase activity of eRF3 in the ribosome. We suggest that GDP binding site of eRF3 acquires an ability to bind gamma-phosphate of GTP if altered by cooperative action of the M and C domains of eRF1. Thus, the stop-codon decoding is associated with the N domain of eRF1 while the GTPase activity of eRF3 is controlled by the MC domain of eRF1 demonstrating a substantial structural uncoupling of these two activities though functionally they are interrelated. |
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Keywords: | termination of translation GTPase ribosome guanine nucleotide binding isothermal titration calorimetry protein–protein interactions |
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