Dynamic regulation of GDP binding to G proteins revealed by magnetic field-dependent NMR relaxation analyses

Yuki Toyama, Hanaho Kano, Yoko Mase, Mariko Yokogawa, Masanori Osawa, Ichio Shimada

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

Heterotrimeric guanine-nucleotide-binding proteins (G proteins) serve as molecular switches in signalling pathways, by coupling the activation of cell surface receptors to intracellular responses. Mutations in the G protein α-subunit (Gα) that accelerate guanosine diphosphate (GDP) dissociation cause hyperactivation of the downstream effector proteins, leading to oncogenesis. However, the structural mechanism of the accelerated GDP dissociation has remained unclear. Here, we use magnetic field-dependent nuclear magnetic resonance relaxation analyses to investigate the structural and dynamic properties of GDP bound Gα on a microsecond timescale. We show that Gα rapidly exchanges between a ground-state conformation, which tightly binds to GDP and an excited conformation with reduced GDP affinity. The oncogenic D150N mutation accelerates GDP dissociation by shifting the equilibrium towards the excited conformation.

Original languageEnglish
Article number14523
JournalNature Communications
Volume8
DOIs
Publication statusPublished - 2017 Feb 22

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ASJC Scopus subject areas

  • Chemistry(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Physics and Astronomy(all)

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