Conformationally restricted elongation factor G retains GTPase activity but is inactive in translocation on the ribosome.

نویسندگان

  • F Peske
  • N B Matassova
  • A Savelsbergh
  • M V Rodnina
  • W Wintermeyer
چکیده

Elongation factor G (EF-G) from Escherichia coli is a large, five-domain GTPase that promotes tRNA translocation on the ribosome. Full activity requires GTP hydrolysis, suggesting that a conformational change of the factor is important for function. To restrict the intramolecular mobility, two cysteine residues were engineered into domains 1 and 5 of EF-G that spontaneously formed a disulfide cross-link. Cross-linked EF-G retained GTPase activity on the ribosome, whereas it was inactive in translocation as well as in turnover. Both activities were restored when the cross-link was reversed by reduction. These results strongly argue against a GTPase switch-type model of EF-G function and demonstrate that conformational mobility is an absolute requirement for EF-G function on the ribosome.

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عنوان ژورنال:
  • Molecular cell

دوره 6 2  شماره 

صفحات  -

تاریخ انتشار 2000