Stabilization of G Domain Conformations in the tRNA-modifying MnmE-GidA Complex Observed with Double Electron Electron Resonance Spectroscopy
Autor(en): | Boehme, Sabine Meyer, Simon Krueger, Andre Steinhoff, Heinz-Juergen Wittinghofer, Alfred Klare, Johann P. |
Stichwörter: | Biochemistry & Molecular Biology; BIOMACROMOLECULES; CODES; EXPRESSION; GENE; GTP-BINDING PROTEIN; INSIGHTS; MTO1; MUTANTS; POSITION | Erscheinungsdatum: | 2010 | Herausgeber: | AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC | Journal: | JOURNAL OF BIOLOGICAL CHEMISTRY | Volumen: | 285 | Ausgabe: | 22 | Startseite: | 16991 | Seitenende: | 17000 | Zusammenfassung: | MnmE is a GTP-binding protein conserved between bacteria and eukarya. It is a dimeric three-domain protein where the two G domains have to approach each other for activation of the potassium-stimulated GTPase reaction. Together with GidA, in a heterotetrameric alpha(2)beta(2) complex, it is involved in the modification of the wobble uridine base U34 of the first anticodon position of particular tRNAs. Here we show, using various spin-labeled MnmE mutants and EPR spectroscopy, that GidA binding induces large conformational and dynamic changes in MnmE. It stimulates the GTPase reaction by stabilizing the GTP-bound conformation in a potassium-independent manner. Surprisingly, GidA binding influences not only the GTP-but also the GDP-bound conformation. Thus GidA is a new type of regulator for a G protein activated by dimerization. |
ISSN: | 00219258 | DOI: | 10.1074/jbc.M109.096131 |
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